System for wirelessly transmitting energy at a near-field distance without using beam-forming control

ABSTRACT

Systems and methods for controlling and managing operation of one or more power amplifiers to optimize the performance of one or more antennas are disclosed. An example wireless-power transmission system includes a power amplifier, one or more antennas, and one or more integrated circuits. The one or more integrated circuits are configured to adjust power provided to the one or more antennas from a power amplifier and adjust a power distribution for the transmission field based, in part, on the adjusted power provided to the one or more antennas from the power amplifier such that the adjusted power provided is evenly distributed across the power distribution for the transmission field of the antenna. The even distribution of the adjusted power results in a reduced power loss at an edge of the power distribution for the transmission field of the antenna from 30% to 10%.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.17/234,696, filed on Apr. 19, 2021, entitled “System For WirelesslyTransmitting Energy Without Using Beam-Forming Control,” which is acontinuation of U.S. patent application Ser. No. 16/932,631, filed onJul. 17, 2020, entitled “System For Wirelessly Transmitting Energy At ANear-Field Distance Without Using Beam-Forming Control,” which claimspriority from U.S. Provisional Patent Application No. 62/955,864, filedDec. 31, 2019, entitled “System For Wirelessly Transmitting Energy At ANear-Field Distance Without Using Beam-Forming Control,” and U.S.Provisional Patent Application No. 63/012,914, filed Apr. 20, 2020,entitled “System For Wirelessly Transmitting Energy At A Near-FieldDistance Without Using Beam-Forming Control, And Systems and Methods ForClassifying And Detecting Foreign Objects Using A Power AmplifierController Integrated Circuit In Wireless Power Transmission Systems,”and these related applications are hereby incorporated by reference intheir respective entireties.

TECHNICAL FIELD

The present disclosure relates generally to systems for wireless-powertransmission, and more particularly to classifying and detectingwireless-power receivers in a wireless charging system using a poweramplifier controller integrated circuit (in conjunction with one or moreadditional sensors), and also to wirelessly transmitting energy at anear-field distance without using beam-forming control.

BACKGROUND

Wireless charging systems for consumer devices typically requirecomplicated, and often, expensive components to transmit and receivewirelessly delivered power. Conventionally, it is difficult for awireless power transmitter to accurately distinguish a valid wirelesspower receiver that needs to be charged, versus a foreign object thatdoes not need to be charged. Users have encountered numerous frustratingissues with some conventional charging devices, including having damagecaused to objects that include magnetic strips and/or RFID chips (e.g.,credits cards, security badges, passports, key fobs, and the like).Moreover, many of these conventional charging devices typically requireplacing the device to be charged at a specific position around thewireless power transmitter, and the device may not be moved to differentpositions, without interrupting or terminating the charging of thedevice. This results in a frustrating experience for many users as theymay be unable to locate the device at the exact right position withinthe charging field of the wireless power transmitter in which to startcharging their device, and may further end up with damages to importantobjects that they use on a daily basis. Furthermore, conventionalwireless charging systems do not utilize a dedicated power amplifiercontroller integrated circuit, let alone one capable of assisting withthe classification and detection of foreign objects.

In addition, existing solutions for the wireless transmission of energyhave been focused on beam-forming solutions that require formation ofmultiple beams of energy, in which beams are formed to create focusedenergy in an operational area. To create this focused energy, manyexisting solutions use beam-forming, e.g., controlling phase and otherwaveform characteristics to produce constructive and/or destructiveinterference patterns to focus power beams onto a device at a certainlocation. Beam-forming typically requires multiple antennas,beam-forming algorithm control circuitry and/or algorithms, and multiplepower amplifiers, all of which add complexity to the system, and add tooverall system costs.

As such, it would be desirable to provide systems and methods forwirelessly transmitting and receiving power that address theabove-mentioned drawbacks.

SUMMARY

The wireless-power transmission system described herein makes itpossible to control a radiation profile using only a single poweramplifier continuously during the charging operation to maintain a powerlevel within the transmission field that is controlled to remain withina safe threshold for human beings (and other potentially sensitiveobjects), thereby addressing some of the problems identified above. Thepresence of a foreign object can also be detected (e.g., when nearand/or on a charging surface, and/or at greater distances with data fromone or more sensors) and the power amplifier controller can be used tohelp produce a selected radiation profile that ensures the system isoperating safely (both to protect human users and other sensitiveobjects, and also to protect system components, such as the poweramplifier, as is discussed in more detail below concerning the one ormore safety thresholds). Various radiation profiles can be predeterminedbased on simulation, characterization, and/or manufacturing tests of thewireless-power transmitter device and/or one or more antennas of thetransmitter device. In some embodiments, the various radiation profilesare predetermined based on one or more of: transmit power (powerreceived from one or more power amplifiers), static or dynamic antennatuning (e.g., moving and/or realigning the antenna positions, changingwhich feed is turned on for a particular antenna, changing physicalcharacteristics of one or more antennas, changing a phase used to feedvarious antennas (not to focus power at a specific receiver location,but instead to cause the radiation profile to shift generally to theleft or to the right), etc.).

In some embodiments, adjustments performed by the wireless-powertransmission system are based on predetermined properties and/orcharacteristics of a wireless-power transmitter device and/or one ormore antennas of the transmitter device obtained during simulation,characterization, and/or manufacturing tests. The predeterminedproperties and/or characteristics of the wireless-power transmitterdevice and/or one or more antennas of the transmitter device areobtained for different operating conditions (e.g., operating powerlevel, number of wireless-power receivers in a transmission area,location of the receivers, etc.) and/or configurations of thewireless-power transmitter device (e.g., number of antennas, poweramplifiers, etc.). These predetermined properties and/or characteristicscan be determined with reference to one or more Smith charts and thenstored in a data structure (e.g., a lookup table) for reference inselecting appropriate operational values (as discussed in more detailbelow with respect to selecting an appropriate operational impedance).

In some embodiments, the wireless-power transmission techniques (e.g.,selecting an appropriate operational impedance) described herein areinitiated by a wireless-power receivers and/or foreign object (organicor inorganic) coming into contact with the wireless-power transmissionsystem (e.g., a charging surface of the transmitter device).Alternatively or additionally, in some embodiments, the wireless-powertransmission system includes one or more sensors that provide additionalinformation for detecting and/or classifying wireless-power receiversand/or foreign objects within an operating (or working) area (not indirect contact with a charging surface).

In some embodiments, the wireless-power transmission system controlsformation of local RF energy by controlling e-field roll-off, e.g., fastdecrease of the electric field strength with increased distance from theRF transmitter, as described herein. The localized RF energy controlledby the wireless-power transmission system and fast roll-off of thee-field as distance increases from a transmitter meet US andinternational SAR requirements. In some embodiments, e-field roll-offdeterminations and and/or the SAR values for different operatingconditions (e.g., operating power level, number wireless-powerreceivers, location of the receivers, etc.) are determined duringsimulation, characterization, and manufacture tests of thewireless-power transmitter device and/or one or more antennas of thetransmitter device. Thus, the system is able to produce radiationprofiles (selected from among the various radiation profiles discussedabove) that are known to comply with e-field roll-off and SARrequirements (e.g., because the system only operates using values thatare known to produce radiation profiles that were determined to complywith required e-field roll-off and SAR requirements).

The compact, and cost-efficient, design of the wireless-powertransmission system disclosed herein includes a power amplifier (e.g.,in some embodiments only a single power amplifier that feeds a singleantenna) that dynamically changes an electromagnetic field radiationlevel and profile based on information from one or more sensors (e.g.capacitive sensors time-of-flight sensors (e.g., ultrasonictime-of-flight sensors etc.), impedance measurements, and/or frominformation received from wireless-power receivers via an out-of-bandBLE link (or other communication protocol). In some embodiments, thewireless-power transmission system disclosed herein eliminates the needto use a complicated beam-forming system (e.g., even if beam-formingcontrol is available, the system does not need to use it to producecontrolled delivery of wirelessly-transmitted energy) that requiresadditional bulky electronic components, and multiple expensive poweramplifiers to control/feed multiple antennas.

In some embodiments, the wireless-power transmission system disclosedherein includes multiple pairs of antennas and power amplifiers (onlyone power amplifier and one antenna in each pair). Each pair of antennaand power amplifier is responsible for a certain charging area, suchthat the pair of antenna and power amplifier controls charging to anyreceiver that is detected to be within the certain charging area, andthis controlled charging is performed without using any beam-formingcontrol. In some embodiments, the wireless-power transmission systemincludes only one power amplifier that feeds multiple antennas, inaddition to, or as an alternative for, the system including multiplepairs of power amplifiers and antennas (e.g., by feeding differentantennas using a single power amplifier, cost of the overall system isreduced, but the system is still able to assign antennas to variouscharging areas). In some other embodiments, the wireless-powertransmission system disclosed herein includes multiple groups ofantennas and power amplifiers (only one power amplifier and multipleantennas in each group). Each group of multiple antennas and poweramplifier is responsible for a certain charging area, such that thegroup of multiple antennas and power amplifier controls charging to anyreceiver that is detected to be within the certain charging area, andthis controlled charging is performed without using any beam-formingcontrol. The antenna or antennas can support a fixed or programmable RFenergy pattern (or profile) controlled via an RF algorithm at thetransmitter that limits the power amplifier energy level, controls theRF energy pattern, and results in a charging area which is within thelimits of regulatory requirements to meet E-field and SAR levels (forinstance, in compliance with Part 15 or Part 18 of FederalCommunications Commission (FCC) requirements). This is explained in moredetail below, e.g., with reference to FIGS. 3, 5, and 14A-17 .

Different embodiments of wireless-power transmitter device can includei) a single power amplifier and a single antenna, ii) a single poweramplifier and two or more antennas, the power amplifier coupled to eachantenna via one or more feeds, iii) a single power amplifier with two ormore antennas, the power amplifier selectively coupled to an antenna viaone or more switches, iv) a single power amplifier with two or moreantennas, the power amplifier coupled to the antennas via one or moresplitters, v) two or more power amplifiers and a single antenna, vi) twoor more power amplifiers and two or more antenna, a single poweramplifier coupled to a single antenna, vii) two or more power amplifiersand two or more antenna, the power amplifiers dynamically configured tocouple with the antennas. Different combinations of the embodimentsdescribed above can be used. Each of the above-described embodimentsinclude a power amplifier controller integrated circuit, as describedherein, and/or other components to perform the methods described below.

In some embodiments, the wireless-power transmission system describedherein includes a power amplifier controller integrated circuit formanaging and controlling operation of the power amplifier. The poweramplifier controller integrated circuit controls the power amplifier toprovide an RF signal that, when provided to the one or more antennas,causes transmission of RF energy that does not harm humans, foreignobjects, and/or the power amplifier. The power amplifier controllerintegrated circuit can be used to select an appropriate power level thatoptimizes the performance of the power amplifier. The power amplifiercontroller integrated circuit can also be used to detect changes inimpedance, classify a receiver, locate a receiver, and a number of otherfunctions described below with reference to FIGS. 4-13 (e.g., use storedlookup tables to determine safe operating values for the PA based on thedetected changes in impedance).

The wireless-power transmission system disclosed herein includes thefunctionality of a Near Field Plus (NF+) system capable of deliveringwireless-power over the air from a transmitter device to multiplereceivers within a charging area (but not in direct contact with thetransmitter device). The NF+ system is optimized/characterized for cost,performance, and regulatory compliance. An NF+ range, for purposes ofthe present disclosure, refers to the region around the transmitterdevice that is within approximately one and a half wavelengths or less(of a power wave to be transmitted by the transmitter device at acertain frequency). In some embodiments, the wireless-power transmissionsystem described herein can be used in one or more of: near-field, NF+,mid-field, and far-field transmission applications. Near-field refers tothe region around the transmission antenna that is within approximatelyone wavelength or less (of a power wave to be transmitted by thetransmitter device at a certain frequency). Far-field refers to theregion around the transmission antenna that is approximately twowavelengths or more (of a power wave to be transmitted by thetransmitter device at a certain frequency). Mid-field refers to theregion between near field and far field. For example, when the frequencyof a transmission wave is 2.4 GHz, the NF+ range is equal or withinaround 0.188 m, the near-field range is equal or within around 0.125 m,the mid-field range is from around 0.125 m to around 0.25 m, and thefar-field range is equal or greater than around 0.25 m. In anotherexample, when the frequency of the transmission wave is 5 GHz, the NF+range is equal or within around 0.09 m, the near-field range is equal orwithin around 0.06 m, the mid-field range is from around 0.06 m toaround 0.12 m, and the far-field range is equal or greater than around0.12 m.

In one example, references to near-field transmission refer to radiationof electromagnetic waves by an antenna (e.g., the loop antenna describedherein) for distances up to approximately a wavelength of an operatingfrequency of the antenna (e.g., a wavelength of an operating frequencyof 5.8 GHz is approximately 5.17 centimeters, so the near-fieldtransmission distance of the antenna in this example would beapproximately 5.17 centimeters). In some embodiments, the operatingfrequency ranges from 400 MHz to 60 GHz. For the purposes of thefollowing description, a near-field power transmitter (or near-fieldradio-frequency power transmitter) is a wireless-power-transmittingdevice that includes one or more wireless-power transmitters, each ofwhich is configured to radiate electromagnetic waves to receiver devicesthat are located within a near-field distance of the power transmitter(e.g., within 0-5.17 centimeters of the power transmitter, if the one ormore wireless-power transmitters of the power transmitter are using anoperating frequency of 5.8 GHz).

(A1) In accordance with some embodiments, a wireless-power transmissionsystem includes one or more integrated circuits. The one or moreintegrated circuits are configured to receive an indication that awireless-power receiver is located within one meter of thewireless-power transmission system and is authorized to receivewirelessly-delivered power from the wireless-power transmission system.The one or more integrated circuits are configured to, in response toreceiving the indication, select a power level from among a plurality ofavailable power levels at which to amplify a radio frequency (RF) signalusing the power amplifier. The power level can be selected from amongavailable power levels stored in one or more lookup tables (LUT)s, wherethe available power levels have been predetermined to ensure that thesystem will produce a radiation profile that complies with safetyrequirements. The one or more integrated circuits are further configuredto, in accordance with a determination that transmitting the RF signalto the wireless-power receiver would satisfy one or more safetythresholds (e.g., the safety thresholds can include user-safetythresholds and power-amplifier-protection thresholds, thus ensuringsafety for humans and protection of system components), instruct thepower amplifier to amplify the RF signal using the power level to createan amplified RF signal, and provide the amplified RF signal to the oneor more antennas, wherein the one or more antennas are caused to, uponreceiving the amplified RF signal, radiate RF energy that is focusedwithin an operating area that includes the wireless-power receiver whileforgoing any active beamforming control.

(A2) In some embodiments of A1, the selected power level is a maximumpower level from among the plurality of available power levels.

(A3) In some embodiments of any one of A1 and A2, thewireless-power-transmission system includes only a single poweramplifier and the one or more antennas include only a single antenna. Anexample of this is demonstrated and described with reference to FIG. 3 .

(A4) In some embodiments of any one of A1-A3, the one or more safetythresholds include a maximum specific absorption rate (SAR) value of notgreater than 2 W/kg, and the determination that transmitting the RFsignal would satisfy the one or more safety thresholds is made when itis determined that transmitting the RF signal would create a maximum SARvalue of not greater than 2 W/kg at the wireless-power receiver.

(A5) In some embodiments of A4, the one or more safety thresholdsinclude a maximum specific absorption rate (SAR) value of not greaterthan 0.8 W/kg, and the determination that transmitting the RF signalwould satisfy the one or more safety thresholds is made when it isdetermined that transmitting the RF signal would create a maximum SARvalue of not greater than 0.8 W/kg at the wireless-power receiver.

(A6) In some embodiments of any one of A1-A5, the one or more safetythresholds include a predetermined roll-off of 3 dB at a predetermineddistance increment relative to a peak amount of RF energy produced byradiated RF energy, and the determination that transmitting the RFsignal would satisfy the one or more safety thresholds is made when itis determined that transmitting the RF signal would create a peak amountof RF energy at the wireless-power receiver that has the predeterminedroll-off of 3 dB for each predetermined distance increment relative tothe peak amount of RF energy. An example of this is demonstrated anddescribed with reference to FIGS. 16-17 .

(A7) In some embodiments of A6, the predetermined distance increment isabout 8 cm.

(A8) In some embodiments of any one of A1-A7, the one or more integratedcircuits are further configured to determine an operational impedance atthe power amplifier based on an impedance measurement from amongmultiple measurement points of the power amplifier, and the one or moresafety thresholds include impedance thresholds indicating that theoperational impedance is at a safe level, and the determination thattransmitting the RF signal will satisfy the one or more safetythresholds is made when it is predicted that using the power level toamplify the RF signal would keep the operational impedance at the poweramplifier within the impedance thresholds. An example of this isdemonstrated and described with reference to FIGS. 4-5 and 7-13 .

(A9) In some embodiments of A8, the one or more integrated circuits arefurther configured to receive an impedance measurement from among themultiple measurement points of the power amplifier. The one or moreintegrated circuits are configured to utilize the impedance measurementto perform a lookup in the one or more LUTs. Based on the lookup, storedmeasurement values for the two or more parametric parameters arereturned and used to determine an operational impedance (safeoperational impedance) for the power amplifier. The one or moreintegrated circuits are further configured to cause the power amplifierto operate using the power level and the operational impedance. Examplevisual representations of the above features are described below withreference to FIGS. 7-9 .

(A10) In some embodiments of A9, the one or more integrated circuits arefurther configured to determine a dissipation level associated with theoperational impedance (while operating the PA at the power level), anddecrease the power level upon determining that the dissipation levelassociated with the operational impedance is above a dissipationthreshold. An example of this is demonstrated and described withreference to FIGS. 10-13 .

(A1 l) In some embodiments of any one of A9 and A10, the power level isdynamically determined based on stored data retrieved from one or moredata structures while the RF energy is focused within an operating areathat includes the wireless-power receiver, and the system does not useany active beamforming control.

(A12) In some embodiments of any one of A1-A11, the one or moreintegrated circuits are configured to receive, from one or more sensors,a shut-off indication that indicates that an object is within apredefined shut-off distance of the wireless-power transmission system,and in response to receiving the shut-off indication, cause the one ormore antennas to cease radiating the RF energy. An example of this isdemonstrated and described with reference to FIGS. 14A-14E.

(A13) In some embodiments of A12, the predefined shut-off distance isapproximately 20 cm from the wireless-power transmission system.

(A14) In some embodiments of any one of A1-A13, the power level isselected from among the plurality of available power levels of the poweramplifier when the wireless-power receiver is at most 40 cm from thewireless-power transmission system.

(A15) In some embodiments of any one of A1-A14, the power level isselected from among the plurality of available power levels of the poweramplifier when the wireless-power receiver is within 20 cm to 40 cm fromthe wireless-power transmission system.

(A16) In some embodiments of any one of A1-A15, the power level isbetween 2 watts and 15 watts.

(A17) In some embodiments of any one of A1-A16, the one or moreintegrated circuits include a first integrated circuit and a secondintegrated circuit, wherein the first integrated circuit is configuredto receive the indication that the wireless-power receiver is locatedwithin one meter of the wireless-power transmission system and isauthorized to receive wireless charging from the wireless-powertransmission system, and select the power level at which to generate theRF signal, and the second integrated circuit is configured to controland manage one or more operations of the power amplifier includinginstructing the power amplifier to amplify the RF signal. An example ofthis is demonstrated and described with reference to FIGS. 1B-3 .

(A18) In some embodiments of any one of A1-A17, thewireless-power-transmission system further includes a communicationradio coupled to the one or more integrated circuits, wherein thecommunication radio is configured to receive charging information fromthe wireless-power receiver, and the one or more integrated circuits areconfigured to select the power level from among the plurality ofavailable power levels based at least in part on the charginginformation.

(A19) In another aspect, a method includes receiving an indication thata wireless-power receiver is located within one meter of awireless-power transmission system and is authorized to receivewirelessly-delivered power from the wireless-power transmission system.The method includes, in response to receiving the indication, selectinga power level from among a plurality of available power levels at whichto amplify a radio frequency (RF) signal using the power amplifier. Themethod further includes, in accordance with a determination thattransmitting the RF signal to the wireless-power receiver would satisfyone or more safety thresholds, instructing the power amplifier toamplify the RF signal using the power level to create an amplified RFsignal, and providing the amplified RF signal to the one or moreantennas, wherein the one or more antennas are caused to, upon receivingthe amplified RF signal, radiate RF energy that is focused within anoperating area that includes the wireless-power receiver while forgoingany active beamforming control.

(A20) In some embodiments, the method of A19 further includes featuresin accordance with any of A2-A18.

(A21) In accordance with some embodiments, a non-transitory,computer-readable storage medium is provided, the storage medium storinginstructions that, when executed by a processor in a computer, cause thecomputer to perform a method, the method including receiving anindication that a wireless-power receiver is located within one meter ofa wireless-power transmission system and is authorized to receivewirelessly-delivered power from the wireless-power transmission system.The method includes, in response to receiving the indication, selectinga power level from among a plurality of available power levels at whichto amplify a radio frequency (RF) signal using the power amplifier. Themethod further includes, in accordance with a determination thattransmitting the RF signal to the wireless-power receiver would satisfyone or more safety thresholds, instructing the power amplifier toamplify the RF signal using the power level to create an amplified RFsignal, and providing the amplified RF signal to the one or moreantennas, wherein the one or more antennas are caused to, upon receivingthe amplified RF signal, radiate RF energy that is focused within anoperating area that includes the wireless-power receiver, while forgoingany active beamforming control.

(A22) In some embodiments, the storage-medium of A21 further includesinstructions to perform or cause performance of features in accordancewith any of A2-A18.

(B1) In accordance with some embodiments, a wireless-power transmissionsystem, includes a power amplifier including a plurality of measurementpoints that allow measurements of at least an impedance measurement ateach respective measurement point, and one or more integrated circuits.The one or more integrated circuits are configured to receive impedancemeasurements at the plurality of measurement points. In someembodiments, the one or more integrated circuits are configured toreceive data from one or more sensors as well. The one or moreintegrated circuits are configured to detect a presence of a foreignobject within 6 inches of the wireless-power transmission system basedon the received impedance measurements and, optionally, the data fromthe one or more sensors, and adjust radiated radio frequency (RF) energythat is focused within an operating area that includes thewireless-power receiver while the presence of the foreign object isdetected. The one or more integrated circuits are further configured todetect absence of the foreign object within the 6 inches of thewireless-power transmission system based on the received impedancemeasurements and, optionally, the data from the one or more sensors (orlack thereof), and cause the radiation of the RF energy focused withinan operating area that includes a the wireless-power receiver upondetermining that the foreign object is absent. An example of this isdemonstrated and described with reference to FIGS. 4-6 .

(B2) In some embodiments of B1, the one or more integrated circuits arefurther configured to use the plurality of measurement points and/or thedata from the one or more sensors with one or more lookup tables (LUTs)to determine an operational impedance at the power amplifier. An exampleof this is demonstrated and described with reference to FIGS. 7-13 .

(B3) In some embodiments of any one of B1 and B2, the impedancemeasurements at the plurality of measurement points include one or moreof voltage at an output of the power amplifier, voltages at pointsinside a matching network, voltage at a drain of a transistors of thepower amplifier, a DC current and voltage consumed by each stage of thepower amplifier, and thermistors at different stages of the poweramplifier.

(B4) In some embodiments of B3, the plurality of measurement points aremeasured at multiple output power levels of the power amplifier.

(B5) In some embodiments of any one of B1-B4, the power amplifierincludes a thermistor that measures temperature.

(B6) In some embodiments of B5, the thermistor is on a same chip asother components of the power amplifier.

(B7) In some embodiments of any one of B1-B6, the one or more integratedcircuits are further configured to store one or more measurements valuesfrom the plurality of measurement points and/or data from the one ormore sensors for subsequent analysis.

(B8) In some embodiments of any one of B1-B7, the one or more integratedcircuits are further configured to synchronize turn-on of poweramplifier bias circuits, and turn-on of a power amplifier power supplynetwork.

(B9) In some embodiments of B8, the power amplifier includes a singledigital input pin and configured to synchronize turn-on of poweramplifier bias circuits, and turn-on of a power amplifier power supplynetwork via the single digital input pin.

(B10) In some embodiments of any one of B1-B9, the one or moreintegrated circuits are further configured to synchronize shut-down ofvarious components of the power amplifier.

(B11) In some embodiments of B10, the power amplifier includes a singledigital input pin and the one or more integrated circuits are configuredto synchronize shut-down of various components of the power amplifiervia the single digital input pin.

(B12) In some embodiments of any one of B1-B11, the one or moreintegrated circuits are further configured to adjust output power andbias conditions of the power amplifier to maintain optimum efficiencyand output power.

(B13) In some embodiments of B2, the one or more integrated circuits arefurther configured to determine a power level at which to generate theradio frequency (RF) signal that satisfies on one or more poweramplifier operation criteria that protect the power amplifier fromdamage, and a determination that the power level would satisfy the oneor more power amplifier operation criteria is based, at least in part,on the operational impedance at the power amplifier.

(B14) In some embodiments of B13, the one or more integrated circuitsare further configured to instruct the power amplifier to shut down ifthe one or more power amplifier operation criteria is not satisfied.

(B15) In some embodiments of any one of B1-B14, the power amplifier is aGaN (Gallium Nitride) power amplifier.

(B16) In some embodiments of any one of B1-B15, the power amplifier is aClass E amplifier.

(B17) In accordance with some embodiments, a method includes receivingimpedance measurements at a plurality of measurement points from a poweramplifier. The method includes detecting a presence of a foreign objectwithin 6 inches of the wireless-power transmission system based on theprovided impedance measurements, and adjusting radiated radio frequency(RF) energy that is focused within an operating area that includes thewireless-power receiver while the presence of the foreign object isdetected. The method further includes detecting absence of the foreignobject within the 6 inches of the wireless-power transmission system,and causing the radiation of the RF energy focused within an operatingarea that includes the wireless-power receiver upon determining that theforeign object is absent.

(B18) In some embodiments of B17, the method is further configured inaccordance with the features of any of B2-B16.

(B19) In accordance with some embodiments, a non-transitory,computer-readable storage medium is provided, the storage medium storinginstructions that, when executed by a processor in a computer, cause thecomputer to perform a method, the method including receiving impedancemeasurements at a plurality of measurement points from a poweramplifier. The method includes detecting a presence of a foreign objectwithin 6 inches of the wireless-power transmission system based on theprovided impedance measurements, and adjusting radiated radio frequency(RF) energy that is focused within an operating area that includes thewireless-power receiver while the presence of the foreign object isdetected. The method further includes detecting absence of the foreignobject within the 6 inches of the wireless-power transmission system,and causing the radiation of the RF energy focused within an operatingarea that includes the wireless-power receiver upon determining that theforeign object is absent.

(B20) In some embodiments of B19, the storage-medium is furtherconfigured in accordance with the features of any of B2-B16.

(C1) In accordance with some embodiments, a method of operating anantenna is provide, and the method includes dynamically adjusting powerdistribution for a transmission field of the antenna provided to awireless-power receiver. Dynamically adjusting the power distributionfor the transmission field includes, at a power amplifier controllerintegrated circuit (IC), adjusting power provided to the antenna from apower amplifier, and adjusting the power distribution for thetransmission field based on the adjusted power provided to the antennafrom the power amplifier. The power distribution for the transmissionfield is adjusted such that the adjusted power provided is evenlydistributed across the power distribution for the transmission field ofthe antenna, and a power loss at an edge of the power distribution forthe transmission field of the antenna is reduced from 30% to 10%.

(C2) In some embodiments of C1, the power provided to the antenna fromthe power amplifier is adjusted based on the power amplifier controllerIC detecting a change in impedance.

(C3) In some embodiments of C2, the change in impedance is movement ofthe wireless-power receiver.

(C4) In some embodiments of any one of C1-C3, dynamically optimizing thetransmitted power signals is performed independent of tuning theantenna.

(C5) In some embodiments, a non-transitory, computer-readable storagemedium is provided that includes instructions to perform or causeperformance of the features of any of C1-C4.

(C6) In some embodiments, a method is provided to perform or causeperformance of the features of any of C1-C4.

Note that the various embodiments described above can be combined withany other embodiments described herein. The features and advantagesdescribed in the specification are not all inclusive and, in particular,many additional features and advantages will be apparent to one ofordinary skill in the art in view of the drawings, specification, andclaims. Moreover, it should be noted that the language used in thespecification has been principally selected for readability andinstructional purposes, and may not have been selected to delineate orcircumscribe the inventive subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

So that the present disclosure can be understood in greater detail, amore particular description may be had by reference to the features ofvarious embodiments, some of which are illustrated in the appendeddrawings. The appended drawings, however, merely illustrate pertinentfeatures of the present disclosure and are therefore not to beconsidered limiting, for the description may admit to other effectivefeatures.

FIG. 1A is a block diagram of an RF wireless-power transmission systemin accordance with some embodiments.

FIG. 1B is a block diagram showing components of an example RF powertransmission system that includes an RF power transmitter integratedcircuit and antenna coverage areas in accordance with some embodiments.

FIG. 1C is a block diagram showing components of an example RF powertransmitter that includes an RF power transmitter integrated circuitcoupled to an optional switch or/and some optional splitters inaccordance with some embodiments.

FIG. 2A is a block diagram illustrating an example RF power transmitterin accordance with some embodiments.

FIG. 2B is a block diagram illustrating an example receiver device inaccordance with some embodiments.

FIG. 3 is a schematic of an example antenna of a wireless-powertransmitter in accordance with some embodiments.

FIG. 4 illustrates arrangements of measurement points within thewireless power transmitter to detect impedances presented to the poweramplifier in accordance with some embodiments.

FIG. 5 schematically illustrates a system diagram of an impedancemeasurement system comprising a power amplifier controller IntegratedCircuit (IC) and its related circuits and modules in accordance withsome embodiments.

FIG. 6 shows a power amplifier controller engineering diagram inaccordance with some embodiments.

FIG. 7 shows a plot of a Smith chart as a visual aid for representingpossible impedances measured from various measurement points inaccordance with some embodiments.

FIG. 8 shows a plot of a Smith chart as a visual aid for representingpossible impedances measured from other various measurement points inaccordance with some embodiments.

FIG. 9 shows an example mapping of a combination of parametricparameters (measured from various measurement points) on a plot of aSmith chart as a visual aid for determining the operational impedance ofthe power amplifier in accordance with some embodiments.

FIGS. 10 and 11 illustrate different uses of the impedance measurementsin accordance with some embodiments.

FIGS. 12 and 13 illustrate power dissipation checks and power scaling inaccordance with some embodiments.

FIG. 14A is an isometric illustration of a device (e.g., an electronicdevice, such as a smart speaker) with an included wireless-powertransmitter in accordance with some embodiments.

FIG. 14B is a top view of the device with the included wireless-powertransmitter and its charging coverage area in accordance with someembodiments.

FIG. 14C is a side view of the device with the included wireless-powertransmitter in accordance with some embodiments.

FIG. 14D is a top view of the device with the included wireless-powertransmitter and its keep out zone and operational area in accordancewith some embodiments.

FIG. 14E is a top view of the device with the included wireless-powertransmitter, and also illustrating features related to optimization ofthe transmission field in accordance with some embodiments.

FIG. 15A is an exploded view of the device with the includedwireless-power transmitter, according to some embodiments.

FIG. 15B is a side cross-sectional view illustration of the device withthe included wireless-power transmitter, according to some embodiments.

FIG. 15C is a transparent illustration of the device with the includedwireless-power transmitter, according to some embodiments.

FIG. 16 illustrates an example of the RF energy focused within anoperating area that includes the location of a wireless-power receiverdecaying or rolling-off by a predetermined amount at a predetermineddistance increment from the peak amount of RF energy in accordance withsome embodiments.

FIG. 17 is an illustration of a measured electric field plot and 2Dgraph to demonstrate electric field roll-off below 10 dB from a peakvalue at about 3 dB for every 8 cm for the device with the includedwireless-power transmitter, according to some embodiments.

FIG. 18 is a flow diagram showing a method of wirelessly-transmittingenergy to a receiver device without using active beam-forming control inaccordance with some embodiments.

FIG. 19 is a flow diagram showing a method of detecting a foreign objectbased on taking measurements at various measurements points of a poweramplifier, in accordance with some embodiments.

FIGS. 20A-20D are flow diagrams showing a method ofwirelessly-transmitting energy to a receiver device without using activebeam-forming control in accordance with some embodiments.

FIGS. 21A-21C are flow diagrams showing a method of controlling and/ormanaging operation of one or more power amplifiers in accordance withsome embodiments.

FIG. 22 is flow diagram showing a method of controlling and/or managingoperation of one or more power amplifiers to optimize the performance ofone or more antennas in accordance with some embodiments.

FIG. 23 is an example flow diagram for selecting an operationalimpedance for a power amplifier in conjunction with transmitting RFenergy from a wireless-power transmitting device in accordance with someembodiments

In accordance with common practice, the various features illustrated inthe drawings may not be drawn to scale. Accordingly, the dimensions ofthe various features may be arbitrarily expanded or reduced for clarity.In addition, some of the drawings may not depict all of the componentsof a given system, method or device. Finally, like reference numeralsmay be used to denote like features throughout the specification andfigures.

DETAILED DESCRIPTION

Numerous details are described herein in order to provide a thoroughunderstanding of the example embodiments illustrated in the accompanyingdrawings. However, some embodiments may be practiced without many of thespecific details, and the scope of the claims is only limited by thosefeatures and aspects specifically recited in the claims. Furthermore,well-known processes, components, and materials have not been describedin exhaustive detail so as not to unnecessarily obscure pertinentaspects of the embodiments described herein.

In some existing wireless-power charging systems using beam-forming, apocket of energy can be formed at locations where power wavestransmitted by a transmitter constructively interfere. The pockets ofenergy may manifest as a three-dimensional field where energy may beharvested by receivers located within or proximate to the pocket ofenergy. In operation, the pocket of energy produced by the transmittersduring pocket-forming processes may be harvested by a receiver,converted to an electrical charge, and then provided to an electronicdevice (e.g., laptop computer, smartphone, rechargeable battery)associated with the receiver to operate the device or to charge thedevice's battery.

“Pocket-forming” may refer to generating one or more RF waves thatconverge in a transmission field, forming controlled pockets of energyand null spaces. A “pocket of energy” may refer to an area or region ofspace where energy or power may accumulate based on a convergence ofwaves causing constructive interference at that area or region. The“null-space” may refer to areas or regions of space where pockets ofenergy do not form, which may be caused by destructive interference ofwaves at that area or region.

The conventional use of beam-forming may require multiple antennas andmultiple power amplifiers, and complex algorithms to effectively chargean electronic device coupled with a wireless-power receiver. Thatapproach can require complicated and expensive equipment and processes.In contrast, the wireless-power transmission systems and methodsdisclosed herein may use a single power amplifier to control a powertransmission level and profile of an antenna's radiated energy, whilestill keeping radiated power levels in the transmission range of theantenna within a safe level that also complies with various regulatoryrequirements. In this way, the inventive systems and methods describedherein are able to use a minimal number of system components (e.g., asingle power amplifier, and no beam-forming components, or is able todisable use of beam-forming components) to achieve safe transmission ofwirelessly-delivered energy in both consumer and commercialenvironments.

A transmitter device can be an electronic device that comprises, or isotherwise associated with, various components and circuits responsiblefor, e.g., generating and transmitting power waves, forming transmissionenergy within a radiation profile at locations in a transmission field,monitoring the conditions of the transmission field, and adjusting theradiation profile where needed. The radiation profile described hereinrefers to a distribution of energy field within the transmission rangeof a transmitter device or an individual antenna (also referred to as a“transmitter”). As was discussed above, various radiation profiles canbe available to the transmitter device, where the various radiationprofiles are predetermined based on simulation, characterization, and/ormanufacture tests of the transmitter device to ensure that eachradiation profile complies with e-field roll-off and SAR requirements.

The transmitter device may generate and transmit, or otherwise adjust,transmitted RF power so that the SAR value for the RF energy at aparticular location in an operating area of the transmitter device doesnot exceed a predetermined SAR threshold value (this determinationregarding the SAR value can be conducted based on ad-hoc measurements,or can be based on expected SAR values that are based on simulation,characterization, and/or manufacture tests of the transmitter device).Safety techniques that can be utilized by the transmitter are describedin more detail below. In some embodiments in which the transmitterdevice uses expected SAR values, the transmitter device does not need toperform ad-hoc measurements of SAR, thus, the wireless-power transmitterdevice can determine whether the predetermined SAR threshold issatisfied without the need of additional processing (e.g., forgoing SARcalculations during operation by referencing stored SAR values for whenthe transmitter device is using certain operating characteristics suchas PA output power, transmission frequency, etc.).

In some embodiments, the wireless-power transmitter device is configuredto produce its radiation profile within an operating area (also referredto as a working area). In some embodiments, the operating area isdirectly in front of the transmitter and/or an area around thetransmitter device in which power can be received by a wireless-powerreceiver above some minimum threshold (e.g., minimum power to charge thewireless-power receiver, as described herein). In some embodiments, theoperating area is typically expressed in radius/angle format (asdiscussed in more detail below). In some embodiments, the operating areais a function of: i) the transmit power, ii) the transmit antennaradiation profile (as described above), the receiver antenna receptionpattern (e.g., receiver of the wireless-power receiver), thewireless-power receiver power conversion efficiency. In someembodiments, the operating area is further a function of tabletopmaterial and/or RF channel properties. The operating area is describedin detail below in reference to, e.g., FIGS. 14D and 14E.

In some embodiments, the wireless-power transmitter device includes ankeep out area (also referred to as a keep out zone). In someembodiments, the keep out zone is an area around the transmitter devicein which one or more safety thresholds will not be satisfied (asdescribed below). In some embodiments, the keep out zone is an areaaround the transmitter device in which, at a minimum, SAR values (e.g.,calculated and/or predetermined by simulation, characterization, and/ormanufacture tests) are above a predetermined SAR threshold. In someembodiments, the keep out zone is typically expressed in radius/angleformat. In some embodiments, the keep out zone is a function of thetransmit power, and/or the transmit antenna radiation profile (asdescribed above). In some embodiments, the keep out zone is further afunction of tabletop material and/or RF channel properties. The keep outzone is described in detain below in reference to FIGS. 14D and 14E.

In some embodiments, the wireless-power transmitter device is a NearField charging pad. In some embodiments, the Near Field charging pad, isconfigured to initiate once a receiver and/or foreign object is inphysical contact with wireless-power transmitter device. In someembodiments, measurements of the antenna (e.g., when the antenna isunloaded/open, or with ideal coupling alignment) are obtained fromfactory manufacture tests, simulations, and/or characterization. In someembodiments, the Near Field charging pad is calibrated at a factory withthe wireless-power transmission system and/or methods disclosed herein.In some embodiments, the wireless-power transmission system and/ormethods are further calibrated to operate with one or more antennasinstalled in the Near Field charging pad. In other words, in someembodiments, the radiation profile, SAR values, data (e.g., impedancevalues) from one or more measurement points, operational scenarios forthe Near Field charging pad, and/or other Near Field charging padconfigurations are determined at a factory and stored in memory for useduring operation. For example, nominal impedance within tolerances forthe Near Field charging pad can be measured during factory calibrationand stored. In some embodiments, during operation, a receiver indifferent positions and state of charge creates a measurable impedancedisplacement from the stored values. In some embodiments, the Near Fieldcharging pad can perform bias correction and/or tuning to protect andoptimize the system performance.

In some embodiments, the wireless-power transmitter device is an NF+system. The NF+ system is configured to operate when a receiver isplaced on and/or near the NF+ system, and/or when the receiver is withinan operational area. In some embodiments, the NF+ system includes one ormore sensors that provide additional data that can be used to performthe operations described herein (e.g., receiver detection and/orclassification). In some embodiments, measurements of the antenna (e.g.,gain and coupling) are obtained from factory manufacture tests,simulations, and/or characterization. In some embodiments, the NF+system is calibrated at a factory with the wireless-power transmissionsystem and/or methods disclosed herein. In some embodiments, thewireless-power transmission system and/or methods are further calibratedto operate with one or more antennas installed in the NF+ system (e.g.,similar to the calibrations discussed above for the NF charging pad).For example, nominal impedance within tolerances for the NF+ system canbe measured during factory calibration and stored. In some embodiments,the NF+ system can perform initial bias correction and/or tuning tooptimize the transmitter device (e.g., NF+ system) in an environment(e.g., location in which the transmitter device operates). In someembodiments, during operation, a receiver in the operating area maycause detectable displacements (e.g., detectable with the assistance ofthe one or more sensors).

In some embodiments, a receiver near to and/or touching the transmitterdevice (e.g., no more than 3 inches between the receiver and a housingof the transmitter device system) will result in a measurabledisplacement that is measured without needing additional data from oneor more sensors to recognize the receiver's presence. In someembodiments, when the receiver is not moving and is near to and/ortouching the transmitter device, the transmitter device (e.g., the NF+system) uses bias correction and/or tuning to protect and optimizesystem performance (as discussed in more detail below concerningselection of an operational impedance). In some embodiments, if thereceiver moves quickly near the transmitter device, the transmitterdevice (e.g., the NF+ system) is caused to trigger receiver acquisitionas disclosed herein.

A receiver (also referred to as a wireless-power receiver) can be anelectronic device that comprises at least one antenna, at least onerectifying circuit, and at least one power converter, which may utilizeenergy transmitted in the transmission field from a transmitter forpowering or charging the electronic device.

FIG. 1A is a block diagram of an RF wireless-power transmission system150 in accordance with some embodiments. In some embodiments, the RFwireless-power transmission system 150 includes a far-field transmitterdevice (not shown). In some embodiments, the RF wireless-powertransmission system 150 includes an RF power transmitter device 100(also referred to herein as a near-field (NF) power transmitter device100 or wireless-power transmitter device 100). In some embodiments, theRF power transmitter device 100 includes an RF power transmitterintegrated circuit 160 (described in more detail below). In someembodiments, the RF power transmitter device 100 includes one or morecommunications components 204 (e.g., wireless communication components,such as WI-FI or BLUETOOTH radios), discussed in more detail below withreference to FIG. 2A. In some embodiments, the RF power transmitterdevice 100 also connects to one or more power amplifier units 108-1, . .. 108-n to control operation of the one or more power amplifier unitswhen they drive external power-transfer elements (e.g., power-transferelements, such as transmission antennas 210-1 to 210-n). In someembodiments, a single power amplifier, e.g. 108-1 is controlling oneantenna 210-1. In some embodiments, RF power is controlled and modulatedat the RF power transmitter device 100 via switch circuitry as to enablethe RF wireless-power transmission system to send RF power to one ormore wireless receiving devices via the TX antenna array 210. In someembodiments, a single power amplifier, e.g. 108-n is controllingmultiple antennas 210-m to 210-n through multiple splitters (110-1 to110-n) and multiple switches (112-1 to 112-n).

In some embodiments, the communication component(s) 204 enablecommunication between the RF power transmitter device 100 and one ormore communication networks. In some embodiments, the communicationcomponent(s) 204 are capable of data communications using any of avariety of custom or standard wireless protocols (e.g., IEEE 802.15.4,Wi-Fi, ZigBee, 6LoWPAN, Thread, Z-Wave, Bluetooth Smart, ISA100.11a,WirelessHART, MiWi, etc.) custom or standard wired protocols (e.g.,Ethernet, HomePlug, etc.), and/or any other suitable communicationprotocol, including communication protocols not yet developed as of thefiling date of this document.

In some embodiments, the communication component(s) 204 receivescharging information from the wireless-power receiver (or from anelectronic device configured to be charged by the wireless-powerreceiver, e.g., a hearing aid that is coupled with the wireless-powerreceiver). In some embodiments the charging information is received in apacket of information that is received in conjunction with an indicationthat the wireless-power receiver is located within one meter of the RFpower transmitter device 100. In some embodiments, the charginginformation includes the location of the wireless-power receiver withinthe transmission field of the RF power transmitter device 100. In someembodiments, the charging information indicates that a receiver isauthorized to receive wirelessly-delivered power from the RF powertransmitter device 100. In other words, the wireless-power receiver canuse a wireless communication protocol (such as BLE) to transmit thecharging information as well as authentication information to the one ormore integrated circuits of the RF power transmitter device 100. In someembodiments, the charging information also includes general informationsuch as charge requests from the receiver, the current battery level,charging rate (e.g., effectively transmitted power or RF energysuccessfully converted to usable energy), device specific information(e.g., temperature, sensor data, receiver requirements orspecifications, etc.), etc.

In some instances, the communication component(s) 204 are not able tocommunicate with wireless-power receivers for various reasons, e.g.,because there is no power available for the communication component(s)to use for the transmission of data signals or because thewireless-power receiver itself does not actually include anycommunication component of its own. As such, in some optionalembodiments, near-field power transmitters described herein are stillable to uniquely identify different types of devices and, when awireless-power receiver is detected, figure out if that wireless-powerreceiver is authorized to receive wireless-power.

FIG. 1B is a block diagram of the RF power transmitter integratedcircuit 160 (the “RFIC”) in accordance with some embodiments. In someembodiments, the RFIC 160 includes a CPU subsystem 170, an externaldevice control interface, an RF subsection for DC to RF powerconversion, and analog and digital control interfaces interconnected viaan interconnection component, such as a bus or interconnection fabricblock 171. In some embodiments, the CPU subsystem 170 includes amicroprocessor unit (CPU) 202 with related Read-Only-Memory (ROM) 172for device program booting via a digital control interface, e.g., an I2Cport, to an external FLASH containing the CPU executable code to beloaded into the CPU Subsystem Random Access Memory (RAM) 174 (e.g.,memory 206, FIG. 2A) or executed directly from FLASH. In someembodiments, the CPU subsystem 170 also includes an encryption module orblock 176 to authenticate and secure communication exchanges withexternal devices, such as wireless-power receivers that attempt toreceive wirelessly delivered power from the RF power transmitter device100.

In some embodiments, the RFIC 160 also includes (or is in communicationwith) a power amplifier controller IC 161A (PAIC) that is responsiblefor controlling and managing operations of a power amplifier, including,but not limited to, reading measurements of impedance at variousmeasurement points within the power amplifier, instructing the poweramplifier to amplify the RF signal, synchronizing the turn on and/orshutdown of the power amplifier, optimizing performance of the poweramplifier, protecting the power amplifier, and other functions discussedherein. In some embodiments, the impedance measurement are used to allowthe RF power transmitter device 100 (via the RFIC 160 and/or PAIC 161A)to detect of one or more foreign objects, optimize operation of the oneor more power amplifiers, assess one or more safety thresholds, detectchanges in the impedance at the one or more power amplifiers, detectmovement of the receiver within the wireless transmission field, protectthe power amplifier from damage (e.g., by shutting down the PA, changinga selected power level of the PA, and/or changing other configurationsof the RF power transmitter device 100), classify a receiver (e.g.,authorized receivers, unauthorized receivers, and/or receiver with anobject), compensate for the power amplifier (e.g., by making hardware,software, and/or firmware adjustments), tune the RF power transmitterdevice 100 system, and/or other functions. Additional detail on the oneor more functions of the PAIC 161A are discussed below in FIGS. 4-6 .

In some embodiments, the PAIC 161A may be on the same integrated circuitas the RF IC 160. Alternatively or additionally, the PAIC 161A may be onits own integrated circuit that is separate from (but still incommunication with) the RF IC 160. In some embodiments, the PAIC 161A ison the same chip with one or more of the Power Amplifiers (PAs) 108. Insome other embodiments, the PAIC 161A is on its own chip that is aseparate chip from the PAs 108. In some embodiments, the PAIC 161A maybe on its own integrated circuit that is separate from (but still incommunication with) the RF IC 160 enables older systems to beretrofitted. In some embodiments, the PAIC 161A as a standalone chipcommunicatively coupled to the RF IC 160 can reduce the processing loadand potential damage from over-heating. Alternatively or additionally,in some embodiments, it is more efficient to design and use twodifferent ICs (e.g., the RF IC 160 and the PAIC 161A).

In some embodiments, executable instructions running on the CPU (such asthose shown in the memory 206 in FIG. 2A, and described below) are usedto manage operation of the RF power transmitter device 100 and tocontrol external devices through a control interface, e.g., SPI controlinterface 175, and the other analog and digital interfaces included inthe RFIC 160. In some embodiments, the CPU subsystem also managesoperation of the RF subsection of the RFIC 160, which includes an RFlocal oscillator (LO) 177 and an RF transmitter (TX) 178. In someembodiments, the RF LO 177 is adjusted based on instructions from theCPU subsystem 170 and is thereby set to different desired frequencies ofoperation, while the RF TX converts, amplifies, modulates the RF outputas desired to generate a viable RF power level.

In the descriptions that follow, various references are made to antennacoverage areas and power-transfer coverage areas, and those terms areused synonymously in this disclosure. In some embodiments, the coveragearea includes an area into which energy is radiated by a particularantenna, which is typically a NF+ distance away from an exterior surfaceof the transmitter's housing that is adjacent to the antenna. In someembodiments, the antenna/power-transfer coverage areas may includeantenna elements that transmit propagating radio frequency waves but, inother embodiments, the antenna/power transfer coverage areas may insteadinclude capacitive charging couplers that convey electrical signals butdo not send propagating radio frequency waves.

In some conventional systems, a viable RF power level can be provided toan optional beam-forming integrated circuit (IC) (not shown), which thenprovides phase-shifted signals to one or more power amplifiers. In suchconventional systems, the optional beam-forming IC is used to ensurethat power transmission signals sent using two or more antennas 210(e.g., each antenna 210 may be associated with a different antenna zone290 or may each belong to a single antenna zone 290) to particularwireless-power receivers are transmitted with appropriatecharacteristics (e.g., phases) to ensure that power transmitted to theparticular wireless-power receiver is maximized (e.g., the powertransmission signals arrive in phase at the particular wireless-powerreceiver). As described herein, the embodiments herein do not requirethe use of a beam-forming integrated circuit. In certain embodiments,such a beam-forming integrated circuit (and/or associated algorithm) canbe included in the systems described herein, but that circuit isdisabled and is not used in conjunction with wirelessly-transmittedenergy to receiver devices.

In some embodiments, the RFIC 160 and/or PAIC 161A provides the viableRF power level (e.g., via the RF TX 178) directly to the one or more PAs108 and does not use any beam-forming capabilities (e.g.,bypasses/disables a beam-forming IC and/or any associated algorithms ifphase-shifting is not required, such as when only a single antenna 210is used to transmit power transmission signals to a wireless-powerreceiver). In some embodiments, the PAIC 161A regulates thefunctionality of the PAs 108 including adjusting the viable RF powerlevel to the PAs 108. In some embodiments, the PAIC 161A has similarstructure as that of the power amplifier controller described in FIG. 5below. The functions of the of the PAIC 161A are discussed below inFIGS. 4-6 .

In some embodiments, the RFIC 160 and/or PAIC 161A provides the viableRF power level (e.g., via the RF TX 178) directly to the one or more PAs108 and does not use a beam-forming IC. In some embodiments, by notusing beam-forming control, there is no active beam-forming control inthe power transmission system. For example, in some embodiments, byeliminating the active beam-forming control, the relative phases of thepower signals from different antennas are unaltered after transmission.In some embodiments, by eliminating the active beam-forming control, thephases of the power signals are not controlled and remain in a fixed orinitial phase. In some embodiments, the PAIC 161A regulates thefunctionality of the PAs 108 including adjusting the viable RF powerlevel to the PAs 108. In some embodiments, the PAIC 161A has similarstructure as that of the power amplifier controller described in FIG. 4below. The functions of the of the PAIC 161A are discussed below inFIGS. 4-6 .

In some embodiments, the one or more PAs 108 then provide RF signals tothe antenna coverage areas 290 (also referred to herein as“power-transfer coverage areas”) for transmission to wireless-powerreceivers that are authorized to receive wirelessly delivered power fromthe RF power transmitter device 100. In some embodiments, each antennacoverage area 290 is coupled with a respective PA 108 (e.g., antennacoverage area 290-1 is coupled with PA 108-1 and antenna coverage area290-N is coupled with PA 108-N). In some embodiments, multiple antennacoverage areas 290 are coupled with a respective PA 108 (e.g., antennacoverage areas 290-M to 290-N are coupled with PA 108-N). In someembodiments, multiple antenna coverage areas are each coupled with asame set of PAs 108 (e.g., a low number (for example, no more thanthree) PAs 108 are coupled with each antenna coverage area 290). Variousarrangements and couplings of PAs 108 to antenna coverage areas 290allow the RF power transmitter device 100 to sequentially or selectivelyactivate different antenna coverage areas in order to determine the mostefficient antenna coverage area 290 to use for transmittingwireless-power to a wireless-power receiver.

In some embodiments, the one or more PAs 108 are also controlled by theCPU subsystem 170 to allow the CPU 202 to measure output power providedby the PAs 108 to the antenna coverage areas of the RF power transmitterdevice 100. In some embodiments, the one or more PAs 108 are controlledby the CPU subsystem 170 via the PAIC 161A. In some embodiments, the PAs108 may include various measurement points that allow for at leastmeasuring impedance values that are used to enable the foreign objectdetection techniques, receiver and/or foreign object movement detectiontechniques, power amplifier optimization techniques, power amplifierprotection techniques, receiver classification techniques, poweramplifier impedance detection techniques, and other techniques describedbelow with reference to FIGS. 4-6 .

FIG. 1B also shows that, in some embodiments, the antenna coverage areas290 of the RF power transmitter device 100 may include one or moreantennas 210A-N. In some embodiments, each antenna coverage area of theplurality of antenna coverage areas includes one or more antennas 210(e.g., antenna coverage area 290-1 includes one antenna 210-A andantenna coverage areas 290-N includes multiple antennas 210; althoughnot shown any antenna coverage area 290 can have multiple antennas). Insome embodiments, a number of antennas included in each of the antennacoverage areas is dynamically defined based on various parameters, suchas a location of a wireless-power receiver on the RF power transmitterdevice 100. In some embodiments, the antenna coverage areas may includeone or more of the loop antenna, meandering line antennas, and/or otherantenna types described in more detail below. In some embodiments, eachantenna coverage area 290 may include antennas of different types (e.g.,a meandering line antenna, a loop antenna, and/or other type ofantenna), while in other embodiments each antenna coverage area 290 mayinclude a single antenna of a same type (e.g., all antenna coverageareas 290 include one loop antenna, meandering antenna, and/or othertype of antenna), while in still other embodiments, the antennascoverage areas may include some antenna coverage areas that include asingle antenna of a same type and some antenna coverage areas thatinclude antennas of different types. In some embodiments theantenna/power-transfer coverage areas may also or alternatively includecapacitive charging couplers that convey electrical signals but do notsend propagating radio frequency waves. Antenna coverage areas are alsodescribed in further detail below.

In some embodiments, only a single antenna is included in each antennacoverage area 290, and, certain embodiments, only a single antennacoverage area 290 with a single antenna is utilized. An example of thisis demonstrated and described with reference to FIG. 3 .

In some embodiments, the RF power transmitter device 100 may alsoinclude a temperature monitoring circuit that is in communication withthe CPU subsystem 170 to ensure that the RF power transmitter device 100remains within an acceptable temperature range. For example, if adetermination is made that the RF power transmitter device 100 hasreached a threshold temperature, then operation of the RF powertransmitter device 100 may be temporarily suspended until the RF powertransmitter device 100 falls below the threshold temperature.

Furthermore, and as explained in more detail below in reference to FIG.2A, the RF power transmitter circuit 160 may also include a secureelement module 234 (e.g., included in the encryption block 176 shown inFIG. 1B) that is used in conjunction with a secure element module 282(FIG. 2B) or a receiver 104 to ensure that only authorized receivers areable to receive wirelessly delivered power from the RF power transmitterdevice 100 (FIG. 1B).

FIG. 1C is a block diagram of a power transmitter system 294 inaccordance with some embodiments. The power transmitter system 294 is anexample of the power transmitter device 100 (FIG. 1A), however, one ormore components included in the power transmitter device 100 are notincluded in the power transmitter system 294 for ease of discussion andillustration.

The power transmitter system 294 includes an RFIC 160, at least one PA108, a PAIC 161A (which may be on the same or a separate IC from the RFpower transmitter IC 160), and a transmitter antenna array 210 havingmultiple antenna coverage areas such as 291-1, 291-2, . . . 291-N. Eachof these components is described in detail above with reference to FIGS.1A and 1B. In some embodiments, the power transmitter system 294includes an optional splitter 293 array (i.e., transmitter-sidesplitter), positioned between the PA 108 and the antenna array 210,having a plurality of splitters 293-A, 293-B, . . . 293-N. The splitterarray 293 is configured to connect the PA 108 with one or more antennacoverage areas 291 of the antenna array 210 in response to controlsignals provided by the RFIC 160. Additionally, the power transmittersystem 294 includes an optional switch matrix 295 (i.e.,transmitter-side switch), positioned between the PA 108 and the antennaarray 210, having a plurality of switches 297-A, 297-B, . . . 297-N. Theswitch matrix 295 is configured to switchably connect the PA 108 withone or more antenna coverage areas 291 of the antenna array 210 inresponse to control signals provided by the RFIC 160. In someembodiments, the switch matrix 295 allows for connections andterminations of different antenna (elements) within the antenna array210.

To accomplish the above, each switch 297 is coupled with (e.g., providesa signal pathway to) a different antenna coverage area 291 of theantenna array 210. For example, switch 297-A may be coupled with a firstantenna 210-1 (FIG. 1B) of the antenna array 210, switch 297-B may becoupled with a second antenna 210-2 of the antenna array 210, and so on.Each of the plurality of switches 297-A, 297-B, . . . 297-N, onceclosed, creates a unique pathway between a PA 108 and a respectiveantenna coverage area of the antenna array 210. Each unique pathwaythrough the switch matrix 295 is used to selectively provide RF signalsto specific antenna coverage areas of the antenna array 210. It is notedthat two or more of the plurality of switches 297-A, 297-B, . . . 297-Nmay be closed at the same time, thereby creating multiple uniquepathways to the antenna array 210 that may be used simultaneously.

In some embodiments, the RFIC 160 (or with the PAIC 161A, or both) is(are) coupled to the switch matrix 295 and is configured to controloperation of the plurality of switches 297-A, 297-B, . . . 297-N(illustrated as a “control out” signal in FIGS. 1A and 1C). For example,the RFIC 160 may close a first switch 297-A while keeping the otherswitches open. In another example, the RFIC 160 may close a first switch297-A and a second switch 297-B, and keep the other switches open(various other combinations and configuration are possible). Moreover,the RFIC 160 is coupled to the PA 108 and is configured to generate asuitable RF signal (e.g., the “RF Out” signal) and provide the RF signalto the PA 108. The PA 108, in turn, is configured to provide the RFsignal to one or more antenna coverage areas of the antenna array 210via the switch matrix 295, and/or the splitters 293 depending on whichswitches 297 in the switch matrix 295 are closed by the RFIC 160. Insome embodiments, when a portion of the circuit segment associated withan antenna within the antenna array 210 is not used, the correspondingswitch 297 will be turned off.

To further illustrate, the power transmitter system can be configured totransmit test power transmission signals, and/or regular powertransmission signals, using different antenna coverage areas, e.g.,depending on a location of a receiver on the power transmitter. In someembodiments, the power transmitter and client devices use standardbluetooth low energy (“BLE”) communications paths to enable powertransmitter to monitor and track the location of the client devices.Accordingly, when a particular antenna coverage area is selected fortransmitting test signals or regular power signals, a control signal issent to the switch matrix 295 from the RFIC 160 to cause at least oneswitch 297 to close. In doing so, an RF signal from at least one PA 108can be provided to the particular antenna coverage area using a uniquepathway created by the now-closed at least one switch 297. In someembodiments, each antenna coverage area 291 includes a single antennas,and only a single antenna coverage area 291 with a single antenna isutilized in certain embodiments.

In some embodiments, the switch matrix 295 may be part of (e.g.,internal to) the antenna array 210. Alternatively, in some embodiments,the switch matrix 295 is separate from the antenna array 210 (e.g., theswitch matrix 295 may be a distinct component, or may be part of anothercomponent, such as the PA 108). It is noted that any switch designcapable of accomplishing the above may be used, and the design of theswitch matrix 295 illustrated in FIG. 1C is merely one example.

FIG. 2A is a block diagram illustrating certain components of an RFpower transmitter device 100 (also sometimes called a transmitter, powertransmitter, or wireless-power transmitter) in accordance with someembodiments. In some embodiments, the RF power transmitter device 100includes an RFIC 160 (and the components included therein, such as aPAIC 161A and others described above in reference to FIGS. 1A-1C),memory 206 (which may be included as part of the RFIC 160, such asnonvolatile memory 206 that is part of the CPU subsystem 170), and oneor more communication buses 208 for interconnecting these components(sometimes called a chipset). In some embodiments, the RF powertransmitter device 100 includes one or more sensors 212 (discussedbelow). In some embodiments, the RF power transmitter device 100includes one or more output devices such as one or more indicatorlights, a sound card, a speaker, a small display for displaying textualinformation and error codes, etc. In some embodiments, the RF powertransmitter device 100 includes a location detection device, such as aGPS (global positioning satellite) or other geo-location receiver, fordetermining the location of the RF power transmitter device 100.

In some embodiments, the one or more sensors 212 include one or morecapacitive sensors, time-of-flight sensors (e.g., ultrasonictime-of-flight sensors), thermal radiation sensors, ambient temperaturesensors, humidity sensors, IR sensors, occupancy sensors (e.g., RFIDsensors), ambient light sensors, motion detectors, accelerometers,and/or gyroscopes.

In some embodiments, the RF power transmitter device 100 furtherincludes an optional signature-signal receiving circuit 240, an optionalreflected power coupler 248, and an optional capacitive charging coupler250.

The memory 206 includes high-speed random access memory, such as DRAM,SRAM, DDR SRAM, or other random access solid state memory devices; and,optionally, includes non-volatile memory, such as one or more magneticdisk storage devices, one or more optical disk storage devices, one ormore flash memory devices, or one or more other non-volatile solid statestorage devices. The memory 206, or alternatively the non-volatilememory within memory 206, includes a non-transitory computer-readablestorage medium. In some embodiments, the memory 206, or thenon-transitory computer-readable storage medium of the memory 206,stores the following programs, modules, and data structures, or a subsetor superset thereof:

-   -   Operating logic 216 including procedures for handling various        basic system services and for performing hardware dependent        tasks;    -   Communication module 218 for coupling to and/or communicating        with remote devices (e.g., remote sensors, transmitters,        receivers, servers, mapping memories, etc.) in conjunction with        wireless communication component(s) 204;    -   Sensor module 220 for obtaining and processing sensor data        (e.g., in conjunction with sensor(s) 212) to, for example,        determine the presence, velocity, and/or positioning of object        in the vicinity of the RF power transmitter device 100;    -   Power-wave generating module 222 for generating and transmitting        power transmission signals (e.g., in conjunction with antenna        coverage areas 290 and the antennas 210 respectively included        therein), including but not limited to, forming pocket(s) of        energy at given locations, and controlling and/or managing the        power amplifier (e.g., by performing one or functions of the        PAIC 161A). Optionally, the power-wave generating module 222 may        also be used to modify values of transmission characteristics        (e.g., power level (i.e., amplitude), phase, frequency, etc.)        used to transmit power transmission signals by individual        antenna coverage areas;    -   Impedance determining module 223 for determining an impedance of        the power amplifier based on parametric parameters obtained from        one or more measurement points within the RF power transmitter        device 100 (e.g. determining an impedance using one or more        Smith charts). Impedance determining module 223 may also be used        to determine the presence of a foreign object, classify a        receiver, detect changes in impedances, detect movement of a        foreign object and/or receiver, determine optimal and/or        operational impedances, as well as a number of other functions        describe below;    -   Database 224, including but not limited to:        -   Sensor information 226 for storing and managing data            received, detected, and/or transmitted by one or more            sensors (e.g., sensors 212 and/or one or more remote            sensors);        -   Device settings 228 for storing operational settings for the            RF power transmitter device 100 and/or one or more remote            devices including, but not limited to, lookup tables (LUT)s            for SAR, e-field roll-off, producing a certain radiation            profile from among various radiation profiles, antenna            tuning parameters, and/or values associated with parametric            parameters of the RF power transmitter device 100 for            different configurations (e.g., obtained during simulation,            characterization, and/or manufacture tests of the RF power            transmitter device 100 and/or updated during operation            (e.g., learned improvements to the system)). Alternatively,            raw values can be stored for future analysis;        -   Communication protocol information 230 for storing and            managing protocol information for one or more protocols            (e.g., custom or standard wireless protocols, such as            ZigBee, Z-Wave, etc., and/or custom or standard wired            protocols, such as Ethernet); and        -   Optional learned signature signals 232 for a variety of            different wireless-power receivers and other objects (which            are not wireless-power receivers).    -   A secure element module 234 for determining whether a        wireless-power receiver is authorized to receive wirelessly        delivered power from the RF power transmitter device 100;    -   An antenna coverage area selecting and tuning module 237 for        coordinating a process of transmitting test power transmission        signals with various antenna coverage areas (e.g., various        antenna coverage areas can combine to produce the operating area        of the transmitter device discussed herein; or, for systems        utilizing a single antenna, that antenna's coverage area can be        the system's operating area) to determine which antenna coverage        area or coverage areas should be used to wirelessly deliver        power to various wireless-power receivers (as is explained in        more detail in reference to FIGS. 9A-9B of PCT Patent        Application No. PCT/US2019/015820, which is incorporated by        reference in its entirety for all purposes; also explained in        more detail in PCT/US2017/065886, which is incorporated by        reference in its entirety for all purposes);    -   An authorized receiver and object detection module 238 used for        detecting various signature signals from wireless-power        receivers and from other objects, and then determining        appropriate actions based on the detecting of the various        signature signals (as is explained in more detail in reference        to FIGS. 9A-9B of PCT Patent Application No. PCT/US2019/015820,        which is incorporated by reference in its entirety for all        purposes; also explained in more detail in PCT/US2017/065886,        which is incorporated by reference in its entirety for all        purposes); and    -   An optional signature-signal decoding module 239 used to decode        the detected signature signals and determine message or data        content. In some embodiments, the module 239 includes an        electrical measurement module 242 to collect electrical        measurements from one or more receivers (e.g., in response to        power beacon signals), a feature vector module 244 to compute        feature vectors based on the electrical measurements collected        by the electrical measurement module 239, and/or machine        learning classifier model(s) 246 that are trained to detect        and/or classify foreign objects.

Each of the above-identified elements (e.g., modules stored in memory206 of the RF power transmitter device 100) is optionally stored in oneor more of the previously mentioned memory devices, and corresponds to aset of instructions for performing the function(s) described above. Theabove-identified modules or programs (e.g., sets of instructions) neednot be implemented as separate software programs, procedures, ormodules, and thus various subsets of these modules are optionallycombined or otherwise rearranged in various embodiments. In someembodiments, the memory 206, optionally, stores a subset of the modulesand data structures identified above.

FIG. 2B is a block diagram illustrating a representative receiver device104 (also sometimes interchangeably referred to herein as a receiver,power receiver, or wireless-power receiver) in accordance with someembodiments. In some embodiments, the receiver device 104 includes oneor more processing units (e.g., CPUs, ASICs, FPGAs, microprocessors, andthe like) 252, one or more communication components 254, memory 256,antenna(s) 260, power harvesting circuitry 259, and one or morecommunication buses 258 for interconnecting these components (sometimescalled a chipset). In some embodiments, the receiver device 104 includesone or more optional sensors 262, such as the one or sensors 212described above with reference to FIG. 2A. In some embodiments, thereceiver device 104 includes an energy storage device 261 for storingenergy harvested via the power harvesting circuitry 259. In variousembodiments, the energy storage device 261 includes one or morebatteries, one or more capacitors, one or more inductors, and the like.

In some embodiments, the power harvesting circuitry 259 includes one ormore rectifying circuits and/or one or more power converters. In someembodiments, the power harvesting circuitry 259 includes one or morecomponents (e.g., a power converter) configured to convert energy frompower waves and/or energy pockets to electrical energy (e.g.,electricity). In some embodiments, the power harvesting circuitry 259 isfurther configured to supply power to a coupled electronic device, suchas a laptop or phone. In some embodiments, supplying power to a coupledelectronic device include translating electrical energy from an AC formto a DC form (e.g., usable by the electronic device).

In some embodiments, the optional signature-signal generating circuit310 includes one or more components as discussed with reference to FIGS.3A-3D of commonly-owned U.S. patent application Ser. No. 16/045,637,which is incorporated by reference in its entirety for all purposes.

In some embodiments, the antenna(s) 260 include one or more of themeandering line antennas that are described in further detail in PCTPatent Application No. PCT/US2017/065886, which is incorporated byreference in its entirety for all purposes (e.g., with particularreference to FIGS. 6A-7D, and elsewhere). In some embodiments, theantenna(s) 260 may also or alternatively include capacitive chargingcouplers (such as those described with reference to FIGS. 5A-5B ofcommonly-owned U.S. patent application Ser. No. 16/045,637, which wasincorporated by reference above) that correspond in structure to thosethat may be present in a near-field power transmitter.

In some embodiments, the receiver device 104 includes one or more outputdevices such as one or more indicator lights, a sound card, a speaker, asmall display for displaying textual information and error codes, etc.In some embodiments, the receiver device 104 includes a locationdetection device, such as a GPS (global positioning satellite) or othergeo-location receiver, for determining the location of the receiverdevice 104.

In various embodiments, the one or more sensors 262 include one or morethermal radiation sensors, ambient temperature sensors, humiditysensors, IR sensors, occupancy sensors (e.g., RFID sensors), ambientlight sensors, motion detectors, accelerometers, and/or gyroscopes. Itis noted that the foreign object detection techniques can operatewithout relying on the one or more sensor(s) 262.

The communication component(s) 254 enable communication between thereceiver 104 and one or more communication networks. In someembodiments, the communication component(s) 254 are capable of datacommunications using any of a variety of custom or standard wirelessprotocols (e.g., IEEE 802.15.4, Wi-Fi, ZigBee, 6LoWPAN, Thread, Z-Wave,Bluetooth Smart, ISA100.11a, WirelessHART, MiWi, etc.) custom orstandard wired protocols (e.g., Ethernet, HomePlug, etc.), and/or anyother suitable communication protocol, including communication protocolsnot yet developed as of the filing date of this document. It is notedthat the foreign object detection techniques can operate without relyingon the communication component(s) 254.

The communication component(s) 254 include, for example, hardwarecapable of data communications using any of a variety of custom orstandard wireless protocols (e.g., IEEE 802.15.4, Wi-Fi, ZigBee,6LoWPAN, Thread, Z-Wave, Bluetooth Smart, ISA100.11a, WirelessHART,MiWi, etc.) and/or any of a variety of custom or standard wiredprotocols (e.g., Ethernet, HomePlug, etc.), or any other suitablecommunication protocol, including communication protocols not yetdeveloped as of the filing date of this document.

The memory 256 includes high-speed random access memory, such as DRAM,SRAM, DDR SRAM, or other random access solid state memory devices; and,optionally, includes non-volatile memory, such as one or more magneticdisk storage devices, one or more optical disk storage devices, one ormore flash memory devices, or one or more other non-volatile solid statestorage devices. The memory 256, or alternatively the non-volatilememory within memory 256, includes a non-transitory computer-readablestorage medium. In some embodiments, the memory 256, or thenon-transitory computer-readable storage medium of the memory 256,stores the following programs, modules, and data structures, or a subsetor superset thereof:

-   -   Operating logic 266 including procedures for handling various        basic system services and for performing hardware dependent        tasks;    -   Communication module 268 for coupling to and/or communicating        with remote devices (e.g., remote sensors, transmitters,        receivers, servers, mapping memories, etc.) in conjunction with        communication component(s) 254;    -   Optional sensor module 270 for obtaining and processing sensor        data (e.g., in conjunction with sensor(s) 262) to, for example,        determine the presence, velocity, and/or positioning of the        receiver 103, a RF power transmitter device 100, or an object in        the vicinity of the receiver 103;    -   Wireless power-receiving module 272 for receiving (e.g., in        conjunction with antenna(s) 260 and/or power harvesting        circuitry 259) energy from, capacitively-conveyed electrical        signals, power waves, and/or energy pockets; optionally        converting (e.g., in conjunction with power harvesting circuitry        259) the energy (e.g., to direct current); transferring the        energy to a coupled electronic device; and optionally storing        the energy (e.g., in conjunction with energy storage device        261);    -   Database 274, including but not limited to:        -   Sensor information 276 for storing and managing data            received, detected, and/or transmitted by one or more            sensors (e.g., sensors 262 and/or one or more remote            sensors);        -   Device settings 278 for storing operational settings for the            receiver 103, a coupled electronic device, and/or one or            more remote devices; and        -   Communication protocol information 280 for storing and            managing protocol information for one or more protocols            (e.g., custom or standard wireless protocols, such as            ZigBee, Z-Wave, etc., and/or custom or standard wired            protocols, such as Ethernet);    -   A secure element module 282 for providing identification        information to the RF power transmitter device 100 (e.g., the RF        power transmitter device 100 uses the identification information        to determine if the wireless-power receiver 104 is authorized to        receive wirelessly delivered power); and    -   An optional signature-signal generating module 283 used to        control (in conjunction with the signature-signal generating        circuit 310) various components to cause impedance changes at        the antenna(s) 260 and/or power harvesting circuitry 259 to then        cause changes in reflected power as received by a        signature-signal receiving circuit 240.

Each of the above-identified elements (e.g., modules stored in memory256 of the receiver 104) is optionally stored in one or more of thepreviously mentioned memory devices, and corresponds to a set ofinstructions for performing the function(s) described above. Theabove-identified modules or programs (e.g., sets of instructions) neednot be implemented as separate software programs, procedures, ormodules, and thus various subsets of these modules are optionallycombined or otherwise rearranged in various embodiments. In someembodiments, the memory 256, optionally, stores a subset of the modulesand data structures identified above. Furthermore, the memory 256,optionally, stores additional modules and data structures not describedabove, such as an identifying module for identifying a device type of aconnected device (e.g., a device type for an electronic device that iscoupled with the receiver 104).

In some embodiments, the near-field power transmitters disclosed hereinmay use adaptive loading techniques to optimize power transfer. Suchtechniques are described in detail in commonly-owned andincorporated-by-reference PCT Application No. PCT/US2017/065886 and, inparticular, in reference to FIGS. 3A-8 and 12-15 of PCT Application No.PCT/US2017/065886.

As one of skill will appreciate upon reading this disclosure, manydifferent antennas can be utilized in the systems described herein. Oneexample is an antenna with a number of different feeds that can each beselectively activated, as is schematically depicted in FIG. 3 , which isa schematic of an example transmitter 300 in accordance with someembodiments. In some embodiments, the antenna 302 is responsible forservicing (e.g., transmitting power to receiver devices located within)a representative transmitter coverage area 290-1 of one of thetransmitter coverage areas 290-1-290-N (FIG. 1 ).

As a non-limiting example, a transmitter 300 (which includes an antennaelement 302, one or more feeds 304-A, 304-B, . . . 304-N, and a poweramplifier 306 (e.g., a single power amplifier). The components of thetransmitter 300 are coupled via busing 316 or the components aredirectly coupled to one another. Additionally, the representativetransmitter 300 includes switches 308-A, 308-B, . . . 308-N positionedbetween the power amplifier 306 and each respective feed 304.

In some embodiments, the power amplifier 306 and any switches 308 can beconfigured as part of the transmitter 300 (not illustrated) while, inother embodiments, the power amplifier 306 and any switches 308 can beconfigured as external to the transmitter 300 and coupled to feeds of anantenna element 302 (as illustrated in FIG. 3 ). In some embodiments,power amplifier 306 may be shared across multiple transmitter coverageareas 290-1.

The antenna element 302 can be coupled with the one or more feeds 304-A,304-B, . . . 304-N. In some embodiments (as shown in FIG. 3 ), theantenna element 302 is directly coupled with each of the feeds 304-A,304-B, . . . 304-N. The antenna element 302 is used to radiate one ormore RF signals that provide wirelessly delivered power to a receiver104. In some embodiments, the radiated one or more RF signals arereceived by the receiver 104 when the receiver is located anywherebetween a top surface of the transmitter coverage area 290-1 and up to awavelength of an operating frequency of the transmitter 300 away fromthe transmitter coverage area 290-1 (e.g., the receiver 104 is within anear-field transmission distance of the transmitter 300). In someembodiments, the antenna element 302 is a conductive wire forming a loopantenna (e.g., a substantially contiguous loop antenna). The antennaelement 302 may be made from a suitable material that is capable ofconducting the RF signals. In some embodiments, the antenna element 302is any antenna type described below.

Each feed 304 can be coupled with the antenna element 302 at a differentposition on the antenna element 302. For example, the feed 304-A iscoupled with the antenna element 302 at a first position, the feed 304-Bis coupled with the antenna 302 at a second position, and so on. Each ofthe one or more feeds 304-A, 304-B, . . . 304-N provides the one or moreRF signals to be radiated by the antenna element 302 at a particularposition along the antenna element 302 (as explained in more detailbelow). Each feed 304 may be made from any suitable conductive material(e.g., aluminum, copper, etc.).

The power amplifier 306 can be used to selectively provide power to oneor more of the feeds 304-A, 304-B, . . . 304-N by closing one or more ofthe switches 308-A, 308-B, . . . 308-N. The power amplifier 306 may beinstructed (e.g., by the controller 309) to close a respective switch ofthe one or more of the switches 308-A, 308-B, . . . 308-N depending on alocation of the receiver 104 relative to the one or more feeds304-A-304-D. In some embodiments, the controller 309 includes anoptional power amplifier controller IC 330 similar to the PAIC 161Adepicted in FIGS. 1B-1C. In some embodiments, the controller 309 isincluded in the RFIC 160. In some embodiments, the controller 309includes one or more processors 318. Although not shown, the one or moreof the switches 308-A, 308-B, . . . 308-N may be part of (e.g., internalto) the power amplifier 306. Operation of the power amplifier 306 isdiscussed in further detail below with reference to the method 1800.

In some embodiments, the power amplifier 306 is coupled with a powersupply (not shown), and the power amplifier 306 draws energy from thepower supply to provide RF signals to one or more of the feeds 304-A,304-B, . . . 304-N. Moreover, in some embodiments (not shown), the poweramplifier 306 is coupled with an RF power transmitter integrated circuit(e.g., the RF integrated circuit may be part of the transmitter coveragearea 290-1 or more generally part of the transmitter device 100. Forexample, the RF integrated circuit is the RFIC 160 as shown in FIGS.1B-1C, and 2A). The RF integrated circuit is configured to generate asuitable RF signal and provide that RF signal to the power amplifier306, and the power amplifier 306 in turn provides the RF signal to oneor more of the feeds 304-A, 304-B, . . . 304-N. In some embodiments, theRF integrated circuit includes an RF oscillator and/or a frequencymodulator that is used to generate the RF signal so that is appropriatefor transmission to an RF receiver 104 (e.g., the RF signal has anappropriate power level, frequency, etc. to ensure that a maximum amountof energy is transferred from the transmitter 300 to the RF receiver104).

In some embodiments, the power amplifier 306 is coupled to an internalor external (with respect to the transmitter 300) controller 309, and inturn is coupled to the one or more processors 318 (FIG. 1A). In someembodiments, the controller 309 and the one or more processors 318 arenot part of a particular transmitter coverage area 290-1 (e.g., thecontroller 309 is an internal component of the transmitter device 100overall and is in communication with each of the transmitter coverageareas 290-1). Alternatively, in some embodiments, respective controllers309 and respective one or more processors 318 are each internallyassociated with each of the respective transmitter coverage areas 290-1.The controller 309 and the one or more processors 318 are configured tocontrol operation of the power amplifier 306. For example, thecontroller 309 or the one or more processors 318 may select a respectivefeed of the feed 304-A, 304-B, . . . 304-N based on the location of thereceiver 104 relative to the feeds 304-A, 304-B, . . . 304-N. Further,the controller 309 may send an instruction to the power amplifier 306that causes the power amplifier 306 to feed one or more RF signals tothe respective feed that was selected based on the location of thereceiver.

The one or more antennas may include antenna types for operating infrequency bands, such as roughly 900 MHz to about 100 GHz or other suchfrequency band, such as about 1 GHz, 5.8 GHz, 24 GHz, 60 GHz, and 72GHz. In some embodiments, the one or more antennas may be directionaland include flat antennas, patch antennas, dipole antennas, and anyother antenna for wireless-power transmission. The antenna types mayinclude, for example, patch antennas with heights from about ⅛ inch toabout 6 inches and widths from about ⅛ inch to about 6 inches. The shapeand orientation of the one or more antennas may vary in dependency ofthe desired features of the transmitter 300; the orientation may be flatin X-axis, Y-axis, and Z-axis, as well as various orientation types andcombinations in three-dimensional arrangements. In some embodiments, theone or more antennas can have a loop shape. In some embodiments, the oneor more antennas can have an “H” shape. In some embodiments, the one ormore antennas can have an “L” shape. In some embodiments, the antennacan have a meandering pattern (e.g., an “S” shape) that includes apredetermined number of turns (e.g., at least one turn, three turns,five turns, etc.) The antenna materials may include any material thatmay allow RF signal transmission with high efficiency and good heatdissipation. The number of antennas may vary in relation with thedesired range and power transmission capability of the transmitter 300.In addition, the antenna may have at least one polarization or aselection of polarizations. Such polarization may include verticalpolarization, horizontal polarization, circularly polarized, left handpolarized, right hand polarized, or a combination of polarizations. Theselection of polarizations may vary in dependency of the transmitter 300characteristics. In addition, the antenna may be located in varioussurfaces of the transmitter 300. The antenna may operate in singlearray, pair array, quad array and any other arrangement that may bedesigned in accordance with the one or more parameters. In anotherembodiments, a low number of power amplifiers, for example, 1-5 poweramplifiers, can be used to control the radiation profiles of theantennas in a wireless-power transmission system.

Additional examples of antennas that can be used with the systemsdescribed herein are discussed with reference to FIGS. 3A-3C ofcommonly-owned U.S. Provisional Patent Application Ser. No. 62/955,864,which is incorporated by reference in its entirety for all purposes; andFIGS. 3A-3C of commonly-owned U.S. patent application Ser. No.16/296,145, which is also incorporated by reference in its entirety forall purposes.

As discussed in more detail below, the power amplifier 306 can also beused in a system in which the power amplifier 306 is the sole poweramplifier in the system and that sole power amplifier can be responsiblefor feeding one or multiple antennas. In the example of a system withonly one PA and only one antenna, designing such a system that iscapable of complying with one or more safety thresholds (as disclosedherein) using only a single power amplifier and only a single antennaresults in a low-cost system that is still able to achieve a safetransmission of wireless power, thus producing a system that iscommercially viable both for its ability to comply with regulatoryrequirements and for its ability to be built at a cost point that ispalatable for customers. Such a system also places a lower computingrequirements on the one or more ICs, because less components need to becontrolled, and also because the system does not require any activebeamforming control.

In some embodiments, the output power of the single power amplifier 306is equal or greater than 2 W. In some embodiments, the output power ofthe single power amplifier 306 is equal or less than 15 W. In someembodiments, the output power of the single power amplifier 306 isgreater than 2 W and less than 15 W. In some embodiments, the outputpower of the single power amplifier 306 is equal or greater than 4 W. Insome embodiments, the output power of the single power amplifier 306 isequal or less than 8 W. In some embodiments, the output power of thesingle power amplifier 306 is greater than 4 W and less than 8 W. Insome embodiments, the output power of the single power amplifier 306 isgreater than 8 W and up to 40 W. In some embodiments, a power amplifier(e.g., the single power amplifier 306 or the one or more PAs 108) is avariable power amplifier (VPA) capable of selecting between one or moreof the values described above. In some embodiments, the VPA selectsbetween a low power lever, median power level, or high power level.

In some embodiments, the maximum power radiation distance or powertransmission range for the antenna(s) controlled by the power amplifier306 is equal or less than 6 inches (approximately 15.2 cm). In someembodiments, the maximum power radiation distance or power transmissionrange for the antenna(s) controlled by the power amplifier 306 is about6 inches to one foot (approximately 15.2 cm to 30.5 cm). In someembodiments, the maximum power radiation distance or power transmissionrange for the antenna(s) controlled by the power amplifier 306 is equalor less than 1 meter. In some embodiments, the maximum power radiationdistance or power transmission range for the antenna(s) controlled bythe power amplifier 306 is about one meter. In some embodiments, themaximum power radiation distance or power transmission range for theantenna(s) controlled by the power amplifier 306 is more than one meter.

In some embodiments, by using the single power amplifier 306 with anoutput power range from 2 W to 15 W, the electric field within the powertransmission range of the antenna 302 controlled by the single poweramplifier 306 is at or below a SAR value of 1.6 W/kg, which is incompliance with the FCC (Federal Communications Commission) SARrequirement in the United States. In some embodiments, by using a singlepower amplifier 306 with a power range from 2 W to 15 W, the electricfield within the power transmission range of the antenna 302 controlledby the single power amplifier 306 is at or below a SAR value of 2 W/kg,which is in compliance with the IEC (International ElectrotechnicalCommission) SAR requirement in the European Union. In some embodiments,by using a single power amplifier 306 with a power range from 2 W to 15W, the electric field within the power transmission range of the antenna302 controlled by the single power amplifier 306 is at or below a SARvalue of 0.8 W/kg. In some embodiments, by using a single poweramplifier 306 with a power range from 2 W to 15 W, the electric fieldwithin the power transmission range of the antenna 302 controlled by thesingle power amplifier 306 is at or below any level that is regulated byrelevant rules or regulations. In some embodiments, the SAR value in alocation of the radiation profile of the antenna decreases as the rangeof the radiation profile increases.

In some embodiments, the radiation profile generated by the antennacontrolled by a single power amplifier is defined based on how muchusable power is available to a wireless-power receiver when it receiveselectromagnetic energy from the radiation profile (e.g., rectifies andconverts the electromagnetic energy into a usable DC current), and theamount of usable power available to such a wireless-power receiver canbe referred to as the effective radiated power of an RF signal. In someembodiments, the effective radiated power of the RF signal in apredefined radiation profile is at least 0.5 watts. In some embodiments,the effective radiated power of the RF signal in a predefined radiationprofile is greater than 1 watts. In some embodiments, the effectiveradiated power of the RF signal in a predefined radiation profile isgreater than 2 watts. In some embodiments, the effective radiated powerof the RF signal in a predefined radiation profile is greater than 5watts. In some embodiments, the effective radiated power of the RFsignal in a predefined radiation profile is less or equal to 4 watts.

In some embodiments, the power amplifier used in the power transmissionsystem controls both the efficiency and gains of the output of the poweramplifier. In some embodiments, the power amplifier used in the powertransmission system is a class E power amplifier. In some embodiments,the power amplifier used in the power transmission system is a GaN poweramplifier. The descriptions provided above with respect to PA 306 alsoapply to the PA 108 that was discussed earlier in reference to FIGS.1A-1C.

FIG. 4 illustrates arrangements of measurement points within awireless-power transmission system 400 (system 400 can be a view ofcomponents of the RF power transmitter device 100, FIG. 1A) to detect(e.g., determine) impedances and/or temperatures presented to the poweramplifier 402, according to some embodiments.

In some embodiments, to protect against impedances known to damage thepower amplifier 402 (which can be an instance of the power amplifiers108 or 306 discussed above), a variety of measurement points are placedwithin and around the power amplifier 402. In some embodiments, themeasurement points within the wireless-power transmission system 400 areused to obtain different sets of measurement values for parametricparameters for the power amplifier 402. In some embodiments, thedifferent sets of measurement values for parametric parameters for thepower amplifier 402 correspond to one or more power levels of the poweramplifier, configurations of the wireless-power transmission system 400,detected and/or connected wireless-power receivers, detected foreignobjects (organic, inorganic, animate, and/or inanimate), and/or otheroperational conditions.

In some embodiments, the different sets of measurement values forparametric parameters for the power amplifier 402 are obtained duringsimulation, characterization, and/or manufacturing test of thewireless-power transmission system 400. Alternatively or additionally,in some embodiments, the different sets of measurement values areobtained through characterization of an electronic device (e.g.,wireless-power receiver) and/or foreign object with the wireless-powertransmission system 400. Certain power measurement points (open, short,load) can be calibrated during manufacturing. In some embodiments, thedifferent sets of measurement values for parametric parameters obtainedduring simulation, characterization, and/or manufacturing tests of thewireless-power transmission system 400 can be stored in data structures(e.g., lookup tables) and used to identify valid (or safe) operationalimpedances of a power amplifier. In some embodiments, the validoperational impedances of the power amplifier are used to defineimpedance thresholds as discussed below. In some embodiments, themethods disclosed herein can be performed by a CPU (e.g. RFIC 160 and/orPAIC 161A) referencing different sets of measurement values forparametric parameters stored in memory 206 (e.g., via lookup tables(LUTs). FIGS. 7-13 below are example visual representations showing thehow the different sets of measurement values for parametric parametersobtained during simulation, characterization, and/or manufacturing testof the wireless-power transmission system 400 are used to identify validoperational impedances of a power amplifier (and create the storedvalues for the LUTs).

In some embodiments, different sets of measurement values for parametricparameters for the power amplifier 402 are obtained through periodicpolling and/or interrupts (e.g., during operation). In this way, thewireless-power transmission system 400 can rapidly detect impedancediscontinuities. In some embodiments, impedance conditions determined tobe unsafe to consumers and/or the power amplifier (as described below)will result in the shutdown of the PA. In some embodiments, impedanceconditions determined to be within safe operational boundaries but notoptimal can result in optimization or re-optimization of the poweramplifier (as discussed below). In some embodiments, the different setsof measurement values for parametric parameters for the power amplifier402 obtained through periodic polling and/or interrupts are used toperform lookups in LUTs to determine valid operating impedances for theamplifier and/or to optimize conditions for the wireless-powertransmission system 400.

Examples of parametric parameters of the measurement points include thevoltage at the output of the amplifier 404, voltages at points insidethe matching network 406 and 416, the voltage at the drain of thetransistors 408. In some embodiments, the DC current and voltageconsumed by each stage of the amplifier 402 are measured. For example,the DC current measurement 410 and the voltage measurement 412 are usedto measure the DC current and voltage at different stages of theamplifier 402. Additionally, in some embodiments, thermistors are usedto obtain temperature measurements at different stages of the amplifier402, such as temperature measurement 414 at the power amplifier 402. Insome embodiments, the thermistor is on a same or different integratedchip as other components of the power amplifier. Additional examples ofthe parametric parameters include, but are not limited to, voltage drainpower, DC Power, voltage output, and power dissipation. In someembodiments, measurement values for two or more parametric parameters ofthe measurement points are used to determine (e.g., predict) the outputimpedance of the power amplifier (e.g., by referencing one or morelookup tables).

In some embodiments, an impedance matching network 406 (e.g., atransmission line) may be integrally formed on the antenna structure 418(which can be an instance of any of the antenna structures describedherein, e.g., the transmitter 300 described with reference to FIG. 3 )of the wireless-power transmission system 400. The matching network 406can provide inductive/capacitive impedance matching between the poweramplifier, and the antenna structure 418. In some other embodiments, thewireless-power transmission system 400 can optionally re-tune usingexternal tuning components based on the measurement values forparametric parameters. The external tuning components can includeadjusting one or more switches, capacitors, inductors, micro stripselements. In some embodiments, external tuning components includecomponents of the matching network 406. In some embodiments, theadjustments to the external tuning components are made to cause thesystem to operate at a desired operational impedance.

In some embodiments, a high impedance network is used to reduce theimpact on the performance of the impedance detection. In someembodiments, by incorporating the impedance detection system describedherein (e.g., described in reference to example visual aids representedin FIGS. 4-13 ), a system does not need an isolator or coupler, asdescribed in FIGS. 12 and 13 , to protect a power amplifier and/ordetermine that an RF signal would satisfy one or more safety thresholds.

In some embodiments, the measurements values must be timed preciselywith the power amplifier turn-on so that: the power amplifier 402 doesnot remain on for too long if a foreign object, damaging conditions,and/or changes in impedance are detected; and the measurements valuesare not reading temporary transient conditions associated with start-upor shut-down which may otherwise confound the impedance measurement.

In some embodiments, measurement values can also be taken at multiplepower amplifier output power levels. For example, a set of measurementvalues can be taken at a low power amplifier output power level, at amedian power amplifier output level, and at a high power amplifieroutput level. In some embodiments, the one or more measurement values(e.g., for parametric parameters) from the plurality of measurementpoints are stored (e.g., in memory 206 within LUTs). In someembodiments, the stored measurement values can be referenced duringoperation. Alternatively or additionally, in some embodiments, thestored measurement values (within the LUTs) can be used for subsequentanalysis during operation (e.g., reference by a CPU (RFIC 160 and/orPAIC 161A) to perform the calculations that are visually representedbelow in in FIGS. 7-13 ).

FIG. 5 schematically illustrates a system diagram of an impedancemeasurement system 500 within a wireless-power transmission systemcomprising a PAIC 161A and its related circuits and modules, accordingto some embodiments.

In some embodiments, a PAIC 161A can protect against conditions (e.g.,impedances or other characteristics of the PAIC 161A) known to damagethe power amplifier.

In some embodiments, the PAIC 161A can also detect foreign objectsthrough an analysis of values obtained from the measurement pointsillustrated in FIG. 4 . Alternatively or additionally, in someembodiments, the values obtained from the measurement points illustratedin FIG. 4 are used to determine (e.g., predict) changes in the impedance(e.g., from movement of a wireless-power receiver and/or foreign objectdetected within the wireless-transmission field, a wireless-powerreceiver and/or foreign object entering or leaving thewireless-transmission field, and/or other circumstances that result in achange to the observed impedances).

In some embodiments, the measurement points illustrated in FIG. 4 areused to select a power level among a plurality of available power levelsof the power amplifier, optimize operation of the power amplifier,and/or perform other control and management functions of the poweramplifier (as is described in further detail with reference to theexamples of FIGS. 7-13 ). In some embodiments, the measurement pointsillustrated in FIG. 4 are used determine whether to continue to providepower to the PA and/or whether to shut-down the PA (as is described infurther detail with reference to FIGS. 9-13 ). In some embodiments, thePAIC 161A manages a system power control loop implemented in firmware.

In some embodiments, the wireless power-transmitting system determines,using the PAIC 161A (and, in some circumstances such as when thereceiver is not contacting a charging surface of the system, also usingadditional data from one or more sensors), a location of thewireless-power receiver. As an example, in some embodiments, the one ormore sensors may identify a receiver within the operating area of thewireless power-transmitting system and provide information regarding thereceiver to the wireless power-transmitting system, and the PAIC 161Amay also provide the wireless power-transmitting system with information(e.g., impedance measurement and/or information described herein) thatcan be used together by the wireless power-transmitting system todetermine the location of the wireless-power receiver. In someembodiments, the information includes detected changes in impedance atthe power amplifier as discussed below (e.g., with reference to theexplanatory examples described in FIGS. 7-13 ). In such embodiments, apower level is selected from among the plurality of available powerlevels based at least in part on the location of the wireless-powerreceiver. Alternatively, rather than basing selection of the power levelon the wireless-power receiver's location, in some other embodiments,the system uses a maximum power level that satisfies one or more safetythresholds, and/or one or more power amplifier operation criteria asdiscussed below (e.g., with reference to the explanatory examplesdescribed in FIGS. 7 and 9 ). Alternatively or additionally, in someembodiments, the indication that includes information is received from acommunications radio or component (e.g., BLE).

In some embodiments, the PAIC 161A is used to control and manageoperation and/or calibration of a power amplifier. In some embodiments,the power amplifier (such as the PAs 306, 108, and 402 described above)is a gallium nitride (GaN) power amplifier and/or a Class E amplifier.In some embodiments, the PAIC 161A optimizes the performance of agallium nitride (GaN) power amplifier and/or a Class E amplifier. Insome embodiments, the power amplifier has an on-die or integratedthermistor. In some embodiments, the power amplifier has an integratedthermistor with the thermistor pins 504 connected to the PAIC 161A. Insome embodiments, the on-die or integrated thermistor is used with theGaN power amplifier and/or Class E amplifier.

In some embodiments, the PAIC 161A can synchronize the turn on of allthe modules of the power amplifier, for example, the power amplifierbias circuits, and the power amplifier power supply network. In someembodiments, the PAIC 161A can perform all of the required analogmeasurements. In some embodiments, the PAIC 161A can adjust the outputpower and bias conditions of the power amplifier to maintain optimumefficiency and output power. In some embodiments, the PAIC 161A candetermine if the measurement results could damage the power amplifierand, if so, quickly shutdown the power amplifier. In some embodiments,the PAIC 161A can synchronize the shut-down of various components of thepower amplifier. In some embodiments, the PAIC 161A facilitates thesynchronized turn on and shut-down of the power amplifier via a singledigital input pin of the power amplifier. For example, in someembodiments, the PAIC's 161A uses a single digital input pin to performpower on and/power off sequences of the power amplifier. In someembodiments, adjustments made by the PAIC 161A to the power amplifierand/or other configurations of a wireless-power transmission system arebased on predetermined properties and/or characteristics of thewireless-power transmission system obtained during simulation,characterization, and/or manufacture tests of the wireless-powertransmitter device.

In some embodiments, the PAIC 161A also stores all measurementinformation for subsequent access by Serial Peripheral Interface (SPI)506, to allow for providing that measurement information (e.g., thevalues obtained at the various measurement points of FIG. 4 ) for use bysoftware 508 that is running on a CPU (e.g., CPU 202, FIG. 1B) of the RFpower transmitter integrated chip 160. In some embodiments, the lookuptables described herein can be stored in a memory of the RF powertransmitter IC 160, in a memory of the PAIC 161A, or in a combination inwhich some lookup tables are stored in the memory of the RF powertransmitter IC 160 and other lookup tables are stored in a memory of thePAIC 161A.

In some embodiments, the PAIC 161A has configurable timing andmeasurement interfaces. Therefore, those configurable measurementpoints/interfaces and time settings make the impedance measurementprocess independent of the exact power amplifier implementation.

In some embodiments, the PAIC 161A works in conjunction with the RFIC160 and/or one or more sensors to perform one or more of the functionsas discussed in FIGS. 1B, 1C, 2A, and 3 and described herein (inreference to FIGS. 4-13 ). As mentioned above in FIGS. 1B, 1C, 2A, and 3, the PAIC 161A is configured to control and manage one or moreoperations of the power amplifier (e.g., instruct the power amplifier toamplify the RF signal, determine (e.g., measure/read)measurement/impedance values from among the multiple measurement pointsof the power amplifier, and other features discussed herein). In someembodiments, the PAIC 161A provides impedance measurements (e.g.,measurement values from among the multiple measurement points of thepower amplifier) to the RFIC 160 to perform one or more of the functionsdiscussed below. In some embodiments, additional information (or data)received from the one or more sensors can be used to determine and/orfurther improve receiver detection, classification, and/or locationidentification (e.g., the data received from the one or more sensors canbe used as additional values to reference in conjunction with the datastored in the LUTs that are used to determine an operational impedance,among other things). The one or more functions of the RFIC 160 aredescribed above in FIGS. 1B, 1C, 2A, and 3 . For simplicity, referencesto the one or more functions performed by wireless-power transmissionsystem below will refer to the one or more functions performed by theRFIC 160 in communication with the PAIC 161A and/or one or more sensors.

In some embodiments, the wireless-power transmission system determines(e.g., predicts) whether an RF signal (based on a selected power levelfrom among a plurality of available power levels; discussed above inFIG. 3 ), when amplified by a power amplifier and provided to one ormore antennas to cause the transmission of RF energy to a wireless-powerreceiver, would satisfy one or more safety thresholds. In someembodiments, the wireless-power transmission system makes thedetermination before any RF energy is transmitted to the wireless-powerreceiver to ensure a safe operating environment and/or to protect one ormore power amplifiers of the RF power transmitter device 100. In someembodiments, the above determination is used in selecting an appropriatepower level from among the plurality of available power levels, suchthat one or more safety thresholds will still be satisfied after the RFsignal is transmitted. In some embodiments, the one or more safetythresholds include user-protection thresholds (e.g., SAR values, e-fieldroll-off values, etc.) and also include power-amplifier-protectionthresholds (e.g., values for parametric parameter that reflect when thePA is operating at a safe operating impedance level (for a given outputpower) that will not result in damage to the PA).

Alternatively or additionally, in some embodiments, the wireless-powertransmission system predicts that transmitting the RF signal (based on aselected power level) in the future would result in a formation of RFenergy at the wireless-power receiver that would satisfy the one or moresafety thresholds. In some circumstances, the wireless-powertransmission system determines that a subset (less than all) of the oneor more safety thresholds is satisfied before performing the one or morefunctions discussed herein. In some other embodiments, thewireless-power transmission system determines that all of the one ormore safety thresholds are satisfied before transmitting wireless power.The above described predictions can be determined by using dynamicallyobtained measurements values and referencing the stored values (inmemory 206). Examples of the safety thresholds are discussed in detailbelow.

The one or more safety thresholds used by the wireless-powertransmission system to select an appropriate power level (and anoperational impedance for the power amplifier while it operates at thatappropriate power level) include one or more of: at least one of amaximum specific absorption rate (SAR) value, a predetermined e-fieldroll-off, global maximum and global minimum power levels, impedancethresholds, voltage standing wave ratio (VSWR) thresholds, powerdissipation thresholds. Each of the one or more safety thresholds arediscussed below.

In some embodiments, the one or more safety thresholds include a maximumSAR value of not greater than 2 W/kg. In some other embodiments, themaximum specific absorption rate (SAR) value of not greater than 0.8W/kg. The inventive system described herein is capable of even greatercontrol over the maximum SAR value, such as by ensuring that radiated RFenergy at the wireless-power receiver will create a maximum SAR value ofnot greater than a value of 1.6 W/kg, 1.5 W/kg, 0.7 W/kg, down to avalue as low as 0.5 W/kg. In some embodiments, the wireless-powertransmission system determines that transmitting the RF signal wouldsatisfy the one or more safety thresholds when it determines (e.g., byusing (or referencing) stored values (within LUTs) in memory 206 and/orby making predictions based on the stored values (within LUTs) in memory206) that transmitting the RF signal would create a maximum SAR valuenot greater than the predefined SAR value (e.g., maximum SAR valuesdescribed above).

In some embodiments, the one or more safety thresholds include apredetermined roll-off (between 1-6 dB) at a predetermined distanceincrement relative to a peak amount of RF energy produced by radiated RFenergy. In some embodiments, the wireless-power transmission systemdetermines that transmitting the RF signal would satisfy the one or moresafety thresholds when it is determined (e.g., by using stored values(within LUTs) in memory 206 and/or by making predictions based on thestored values (within LUTs) in memory 206) that transmitting the RFsignal would create a peak amount of RF energy at the wireless-powerreceiver that has the predetermined roll-off for each predetermineddistance increment relative to the peak amount of RF energy. In someembodiments, the predetermined distance increment is about 8 cm. In someembodiments, “about 8 cm” refers to +/−0.5 cm of 8 cm. Other values arealso with the scope of this disclosure and discussed below with respectto FIGS. 16 and 17 . Examples of the predetermined roll-off for eachpredetermined distance increment relative to the peak amount of RFenergy are provided below in FIGS. 16 and 17 . For example, as shown inFIG. 16 , RF energy is focused within an operating area that includesthe location of the receiver and begins to decay (e.g., roll-off)further away from the receiver. While the primary example given here forillustrative purposes is a predetermined 3 dB roll-off value, in someembodiments, other suitable predetermined roll-off values can beutilized (e.g., as described below in FIGS. 16 and 17 ).

The maximum SAR value and predetermined e-field roll-off (or, simply,predetermined roll-off) safety thresholds are referred to as user-safetythresholds as these thresholds are used to ensure transmission ofwireless power in a way that is safe for humans and other sensitiveobjects. In some embodiments, and as was discussed above, satisfactionof the user-safety thresholds can be determined by designing thewireless-power-transmission system to operate using transmissionsettings (e.g., PA output power, frequency, etc.) that ensure the systemwill comply with the user-safety thresholds (e.g., the system undergoessimulation, characterization, and manufacturing tests before the systemis placed into use; while, in other embodiments, the system can makedeterminations concerning satisfaction of the user-safety thresholdswhile the system is in use. In certain circumstances, a combination isutilized in which the system is designed to ensure compliance with theuser-safety checks and the system also performs on-the-flydeterminations to ensure that the user-safety thresholds remainsatisfied during use.

In addition to the user-safety thresholds, the system can also utilizepower-amplifier-protection thresholds, e.g., thresholds designed toensure that the PA will not be damaged while operating at a given outputpower level and a given operating impedance. Examples of thepower-amplifier-protection thresholds include global maximum and globalminimum power levels, impedance thresholds, VSWR thresholds, and powerdissipation thresholds. These examples are discussed in turn below.

In some embodiments, the one or more safety thresholds include globalmaximum and global minimum (output) power levels for the poweramplifier. In some embodiments, receivers (or a device receiving chargetherefrom) can communicate new or updated charging information that thencauses the wireless-power transmission system to select and use a newpower level for amplifying RF signals, provided that the new power levelis within the boundaries of the global max and min values (based on thewireless-power transmission system and stored in memory 206). An exampleof the wireless-power transmission system utilizing communicatedcharging information is shown and described with reference to FIGS.14A-14E).

In some embodiments, the one or more safety thresholds include impedancethresholds. The impedance thresholds indicate that the operationalimpedance of the power amplifier is at a safe level (e.g., within theoperational limits of the power amplifier such that the power amplifierwould not be damaged). In some embodiments, the impedance thresholds areeach associated with a particular measurement point in and around the PA(such that the system can check to verify that the impedance at anyparticular point within the PA is within the associated impedancethreshold. Additionally, or alternatively, the system can use themeasurements from in and around the PA to determine an operatingimpedance for the PA (e.g., an aggregate impedance based on theindividual impedance measurements). In some embodiments, thewireless-power transmission system determines the operational impedanceat the power amplifier based on stored measurement values for parametricparameters (which measurement values are obtained based on theindividual impedance measurements). In some embodiments, thewireless-power transmission system determines that transmitting the RFsignal will satisfy the one or more safety thresholds when it isdetermined (e.g., by referencing LUTs in memory 206 and/or makingpredictions based on the LUTs and the dynamically obtained impedancemeasurements) that using the selected power level to amplify the RFsignal would keep the operational impedance at the power amplifierwithin an impedance threshold. In some embodiments, the operationalimpedance at the power amplifier is determined using one or more of theLUTs described above. For explanatory purposes, the Smith chartsdiscussed below are used to visually represent the information includedin the LUTs (which is derived from these Smith charts). Detaileddescriptions for using the impedance measurements to determine anoperational impedance at the power amplifier are provided in FIGS. 7-13.

Alternatively or additionally, in some embodiments, the operationalimpedance at the power amplifier (e.g., determined based on lookups inthe LUTs using the dynamically obtained impedance measurements) is usedto optimize performance of the power amplifier. For example, if theoperational impedance at the power amplifier is at a level safe but isdetermined to be non-optimal, the wireless-power transmission system mayoptimize or re-optimize the power amplifier through adjustment ofexternal circuit elements (e.g., adjustments to capacitors, inductors,matching networks, etc. as described above in FIG. 4 ). In someembodiments, if the power amplifier is successfully optimized orre-optimized (optimization based on the operational impedance at thepower amplifier), the power provided by the power level can be increasedto an expected maximum value (based on the satisfaction of the one ormore safety thresholds disclosed herein). In particular, the poweramplifier voltages may be optimized or re-optimized through incrementaladjustment and/or re-calibration until the output power or efficiency issafe and/or optimized. In some other embodiments, the PAIC 161A protectsand/or re-optimizes the power amplifier by adjusting hardwarefunctionality and/or the RF power transmitter device 100 firmware.Optimization or power scaling of the wireless-power transmitter device100 is described below and examples are provided in FIGS. 10-13 .

In some embodiments, the one or more safety thresholds include VSWRthresholds. VSWR is a measure of the efficiency in transmittingradio-frequency power from a power source (e.g., the power amplifier) toa load (e.g., an antenna), via a transmission line. In particular, VSWRis a ratio of the maximum voltage to the minimum voltage in standingwave pattern along the length of a transmission line structure. The VSWRthresholds can be obtained during simulation, characterization, and/ormanufacture tests of the wireless-power transmitter device 100 and/orone or more antennas of the transmitter device 100 and stored in memory206 (e.g., in one or more LUTs). The VSWR thresholds can be referencedand/or used to perform the operations disclosed herein. In someembodiments, the VSWR thresholds include different values (e.g., 1, 1.5,2, 2.5, 3, etc.) that are based on the power amplifier (e.g., VSWRlimits of the power amplifier or VSWRs that the power amplifier cansupport without damage). In some embodiments, the VSWR thresholds arebased on other factors such as the housing of the wireless-powertransmitter, the number of components and/or temperature of thewireless-power transmitter, operating scenarios (e.g., number ofreceivers located in the operating area of the system), power levels,and/or configurations of the wireless-power transmitter. In someembodiments, the VSWR thresholds are used by the wireless-powertransmission system to determine whether the wireless-power transmitterdevice 100 needs to perform power scaling. For example, if thewireless-power transmission system determines (using the LUTs or byreferencing the LUTs) that the VSWR thresholds are not satisfied, thewireless-power transmission system can perform power scaling to find anoutput power and operational impedance combination that allows fortransmission of wireless power in a way that will not damage the PA.Detailed descriptions and examples of the VSWR thresholds are providedbelow in FIGS. 10-11 .

In some embodiments, the one or more safety thresholds include a powerdissipation threshold (also referred to as power dissipation limit).Power dissipation is the amount of wasted or unused energy generated bythe power amplifier. In some embodiments, the dissipation threshold isbased on at least the power amplifier and obtained during simulation,characterization, and/or manufacture tests of the wireless-powertransmitter device 100 and/or one or more antennas of the transmitterdevice 100. In some embodiments, the power dissipation limit is 10 W, 15W, 20 W, or other values defined by the power amplifier. In someembodiments, the dissipation limit includes a tolerance of +/−1.5 W. Insome embodiments, the dissipation thresholds are stored in memory 206(e.g., in one or more LUTs). In some embodiments, the dissipationthreshold is based on other factors such as the housing of thewireless-power transmitter, the number of components and/or temperatureof the wireless-power transmitter, operating scenarios, power levels,and/or configurations of the wireless-power transmitter. In someembodiments, in accordance with a determination that the VSWR thresholdsare not (or would not be) satisfied (as described above), thewireless-power transmission system determines whether power scaling isnecessary. In some embodiments, if the wireless-power transmissionsystem determines that a determined power dissipation (e.g., determinedby referencing LUTs in memory 206 and/or referencing LUTs when analyzingan impedance measurement) is greater than a power dissipation threshold,the wireless-power transmission system performs power scaling. In someembodiments, power scaling is the adjustment of a selected power levelof the power amplifier until a maximum power output can be achieved. Insome embodiments, if the wireless-power transmission system determinesthat the determined power dissipations are not greater than the powerdissipation threshold, the wireless-power transmission system forgoesperforming power scaling. Detailed descriptions and examples of thedissipation threshold are provided below in FIGS. 12-13 .

In some embodiments, after determining that the selected power level(while the power amplifier has the operational impedance determinedabove) satisfies the one or more safety thresholds, the wireless-powertransmission system instructs the power amplifier to amplify the RFsignal using the selected power level (while operation with theoperational impedance) to create an amplified RF signal. As describedherein, the wireless-power transmission system performs the abovedescribed functions without any beamforming (e.g. forgoing beamformingto modify the phase, gain, etc., or without having any beamformingcircuitry available in the system at all). In some embodiments, the safepower level at which to generate the RF signal increases as the distancebetween the wireless-power receiver between and the wireless-powertransmission system increases. In some embodiments, if thewireless-power transmission system determines that there is no safepower level at which to generate the RF signal, the wireless-powertransmission system instructs the power amplifier to shut down.

In some embodiments, after instructing the power amplifier, the poweramplifier provides the amplified RF signal to the one or more antennas,the one or more antennas caused to, upon receiving the amplified RFsignal, radiate RF energy that is focused in the operating area thatincludes the wireless-power receiver while forgoing any activebeamforming control. In some embodiments, the system is capable offocusing the RF energy at the wireless-power receiver, which means thata peak level of RF energy is at its maximum at the location of thewireless-power receiver.

As discussed above, in some embodiments, the wireless-power transmissionsystem determines whether: a power level of the power amplifier needs tobe changed, operation of the power amplifier needs to be optimized, thepower amplifier needs to be shut down, the power amplifier can continueto provide power, and/or perform control and/or management functions onthe power amplifier in some way. In some embodiments, one or more ofthese identified functions are performed when the wireless-powertransmission system determines that there is a wireless-power receiverand/or foreign object within the transmission range of thewireless-power transmitter device 100 (e.g., whether the wireless-powerreceiver and/or foreign object is in contact with a charging surface,and/or, while using one or more sensors, the wireless-power transmitterdetects and/or classifies the wireless-power receiver and/or foreignobject in an operating area (further away from the charging surface ofwireless-power transmitter).

In some embodiments, the wireless-power transmission system determines(by using and/or referencing the LUTs) if there is a change in thedetected impedance (e.g., impedance discontinuity based on the impedancemeasurements). In some embodiments, detected changes in impedancetriggers a receiver acquisition loop. The receiver acquisition loop isused to classify a receiver and/or foreign object. In some embodiments,the classifications include the classification could include validreceiver (e.g., authorized receiver), foreign object, and receiver andforeign object. In some embodiments, the detected changes in impedanceare based on movement of a wireless-power receiver and/or foreign objectwithin the wireless-transmission field, a wireless-power receiver and/orforeign object entering and/or leaving the wireless-transmission field,and/or other circumstances that result in a change to the impedance.Classification of a receiver and or foreign object is explained in moredetail in reference to FIGS. 3A-4 and 9A-9B of PCT Patent ApplicationNo. PCT/US2019/015820, which is incorporated by reference in itsentirety for all purposes.

Alternatively or additionally, in some embodiments, an authorizedwireless power receiver is a receiver that has been authorized through asecure component (e.g., secure element module 234) such as anidentification number to receive wireless power from a wireless powertransmission system. In some embodiments, an authorized wireless powerreceiver is a receiver that has been configured to receive wirelesspower from a wireless power transmission system. In some embodiments, areceiver that has not been configured to receive wireless power from awireless-power transmission system is not authorized wireless-powerreceiver. Receivers determined not to be authorized receivers aretreated as foreign objects. Authorization of receivers is discussedabove in reference to FIGS. 2A and 2B.

In some embodiments, the wireless-power transmission system adjusts thepower level and/or or shifts where the RF energy (e.g., by activating adifferent feed point of multiple feed points available for the antenna)is transmitted to avoid any detected foreign objects while the foreignobject(s) is (are) within the transmission range. In some otherembodiments, the wireless-power transmission system stops transmittingRF energy if a foreign object is detected within the transmission range.In some embodiments, while a foreign object is within the transmissionrange, the wireless-power transmission system selects a power leveland/or shifts the transmitted RF energy to focus on an authorizedreceiver and/or avoid damaging the foreign object and/or poweramplifier, if possible. In some embodiments, even if a foreign object isnot within the transmission range, the wireless-power transmissionsystem can select a power level and/or shift the transmitted RF energyto focus on the authorized receiver as discussed herein. As mentionedabove, adjustments to the selected power level, radiation profile (e.g.,static or dynamic antenna tuning), selected active antennas, and/orother adjustments are based on referencing stored values (in LUTs withinmemory 206) obtained during simulation, characterization, and/ormanufacture tests of the wireless-power transmitter device, and/orreferencing the stored values with dynamically obtained measurements.

FIG. 6 shows a power amplifier controller engineering diagram 600,according to some embodiments.

In some embodiments, the power amplifier includes a controller 602(e.g., PAIC 161A). Alternatively or additionally, in some embodiments,the RFIC 160 includes the controller 602. In some embodiments, thecontroller 602 a standalone component coupled to the RFIC 160 and/or thepower amplifier. In some embodiments, the power amplifier controller 602includes an LDO (Low Dropout) 604. In some embodiments, the poweramplifier controller 602 includes an LDO 606. In some embodiments, thepower amplifier controller 602 includes an LDO 608. In some embodiments,the power amplifier controller 602 includes a Bias 610. In someembodiments, the power amplifier controller 602 includes an REG(register) 612. In some embodiments, the power amplifier controller 602includes an SPI (serial peripheral interface) 614. In some embodiments,the power amplifier controller 602 includes an OSC (e.g., on-boardcalibrated oscillator) 616. In some embodiments, the power amplifiercontroller 602 includes an Analog test mux and buffer 618. In someembodiments, the PAIC 161A includes flexible general-purposeinput/output (GPIO) 620.

In some embodiments, the PAIC 161A includes a system status statemachine with programmable alarm thresholds and/or an interruptionrequest (IRQ) generator. In some embodiments, the PAIC's 161A includesmulti-output negative bias control. In some embodiments, the PAIC's 161Aincludes at least one or more of: multi-channel ADCs and DACs, dualpower detectors, and a temperature sensor. In some embodiments, one ormore modules within the power amplifier controller 602 are optional. Forinstance, to control the power amplifier, the PAIC 161A utilizes thesingle digital pin for the power amplifier enable/disable (e.g., poweramplifier sequencing discussed above), the multi-output negative biascontrol, and the on-board calibrated oscillator. To perform impedancedetection/sensing, the PAIC 161A utilizes the system status statemachine with programmable alarm thresholds, the IRQ generator, themulti-channel ADC and DAC, dual power detectors, the temp sensor, theSPI high speed host interface, and the flexible GPIO. In someembodiments, the PAIC 161A can be split into two separate chipsets tocontrol the power amplifier and perform impedance detection/sensing,respectively.

FIGS. 7-13 are provided for illustrative purposes to explain how one ormore LUTs are constructed to reflect measurement values for parametricparameters that are determined during simulation, characterization, andmanufacturing tests of the wireless-power-transmission system. Thus,while FIGS. 7-13 show visual representations of Smith charts and certainvalues for parametric parameters based on those Smith charts, it shouldbe understand that the system need not re-determine the measurementvalues for parametric parameters on-the-fly, instead these values arestored in the LUTs in a memory accessible by a CPU (e.g. RFIC 160 and/orPAIC 161A). For example, impedance measurements from in and around thePA can be used to lookup the stored values in the LUTs for theparametric parameters, and those stored values then allow the system todetermine an operational impedance (or PA output power, or combinationof both) that complies with the one or more safety thresholds describedherein.

FIG. 7 shows a sample plot of a Smith chart 700 representing possibleimpedances measured from the various measurement points discussed abovewith reference to FIG. 4 , in accordance with some embodiments. In someembodiments, different sets of measurement values (based on parametricparameters) are obtained from various measurement points correspondingto the one or more measurement points illustrated above in FIG. 4 . Thedifferent sets of measurement values, when plotted on a Smith chart,represent best operational impedances of the power amplifier. Asmentioned above in reference to FIG. 4 , the different measurement setsare obtained during simulation, characterization, and/or manufacturingtests of the wireless-power transmitter device 100. Alternatively oradditionally, the different sets of measurement values are obtainedthrough characterization of the electronic device (e.g., wireless-powerreceiver) and/or foreign object as these devices/objects are placed nearor on the wireless-power transmitter device 100. The different sets ofmeasurement values correspond to one or more power levels of the poweramplifier, configurations of the wireless-power transmitter device 100,detected and/or connected wireless-power receivers, detected foreignobjects (organic, inorganic, animate, and/or inanimate), and/or otheroperational conditions. In some embodiments, the different sets ofmeasurement values described herein are used to define the impedancethresholds used in conjunction with the one or more safety thresholdsthat were described above.

In some embodiments, the different sets of measurement values are storedand used to determine the operational impedance of a power amplifierbefore and/or while RF energy is provided to a wireless-power receiver(e.g., stored sets of measurement values are used as impedancethresholds; included in the LUTs). For example, stored sets ofmeasurement values can be used as baselines when analyzing dynamically(e.g., during operation) obtained measurement values (referred to asimpedance measurements) to determine the operational impedance of apower amplifier before and/or while RF energy is provided to awireless-power receiver. Similarly, stored sets of measurement valuescan be used as initial baseline for operating the power amplifier beforeany RF energy has been transmitted. The impedance measurements areobtained (dynamically or through periodic polling) from the variousmeasurement points during operation of the wireless-power transmitterdevice 100, and based on parametric parameters. In some embodiments, theimpedance measurements are stored with the sets of measurement valuesobtained during simulation, characterization, and/or manufacturing testsfor future use in determining the operational impedance of a poweramplifier. In this way, performance of the impedance determinationmethods disclosed herein are improved over time. A detailed explanationof the use of one or more plots of Smith charts is described below withreference to FIGS. 9-13 .

In some embodiments, the different sets of measurement values generateone or more contours when plotted (e.g., mapped) on the Smith chart.Each value of the one or more contours plotted on the Smith chartrepresents an operational impedance of the power amplifier. In someembodiments, one or more contours of a first measurement set of thedifferent measurement sets correspond to a first parametric parameterand are generally orthogonal (sometimes referred to as orthogonal forsimplicity below) to one or more contours of a second measurement set ofthe different measurement sets that correspond to a second parametricparameter. In some embodiments, one or more orthogonal contours (e.g.,contours corresponding to the first and second measurement sets) areplotted together on a single Smith Chart. In some embodiments, eachintersection of the one or more orthogonal contours plotted on thesingle Smith chart represents a known operational impedance of the poweramplifier. These representative known operational impedances (based onmeasurement values for at least two parametric parameters) of the poweramplifier are included in the LUTs stored in memory (e.g., memory 206)and used by the wireless-power transmission system and/or methods ofoperational thereof that are described herein. In some embodiments,valid operational values can be predicted based the representation knownoperational impedances (e.g., calculating extrapolations based on therepresentation known operational impedances to determine otherpotentially valid operational impedances; extrapolations that could beincluded in the LUTs stored in memory 206). In some embodiments,portions of the one or more orthogonal contours that do not intersect orintersect multiple times do not map to valid operational impedances(e.g., represent impedances that could damage the power amplifier).These representative invalid (or harmful) impedances (based onmeasurement values for at least two parametric parameters) of the poweramplifier can be included in the LUTs stored in memory (e.g., memory206) and flagged as invalid operational impedances (in some embodiments,the LUTs can be constructed so that the invalid operational impedancesare not included, such that the LUTs only include safe operationalimpedances). In some embodiments, the wireless-power transmitter device100 determines valid and/or invalid operational impedances (e.g.,impedance thresholds) based on the measurement values of at least twoparametric parameters.

Returning to the example plot of Smith chart 700, in some embodiments,the different sets of measurement values for at least two parametricparameters, such as the total voltage at the drain of the poweramplifier 702, and the DC power 704, are plotted on the Smith chart,such that the Smith chart 700 represents possible impedances underdifferent scenarios for a given power level of the PA. In particular,the different measurement sets for the total voltage at the drain of thepower amplifier 702 and the DC power 704 are plotted on the Smith Chart700, and the different measurement sets for the total voltage at thedrain of the power amplifier 702 and the DC power 704 generaterespective contours. In some embodiments, the contours of the differentmeasurement sets for the total voltage at the drain of the poweramplifier 702 and the DC power 704 are generally orthogonal to eachother as shown in FIG. 7 . In some embodiments, the intersections of thecontours of the different measurement sets (based on parametricparameters) corresponds to a valid operating impedance of the one ormore power amplifiers for a wireless-power transmitter device 100. Asdescribed below in reference to the examples in FIGS. 9-13 , in someembodiments, the valid operating impedances can be used to determine(e.g., predict) the operational impedance of the power amplifier basedon one or more impedance measurements before providing power to awireless power receiver and/or during operation of the wireless-powertransmitter device 100.

FIG. 8 shows another example of a plot of a Smith chart 800 representingpossible impedances measured from the various measurement points, inaccordance with some embodiments. Again, the visual depiction reflectsoperations that can be used to populate the one or more LUTs that arethen referenced by the system in use. In some embodiments, differentmeasurement sets for different combinations of parametric parameters canbe used to determine the operational impedance for the power amplifier.For example, different measurement sets for different parametricparameters, such as the Output voltage of the power amplifier 802, andthe Dissipated power 804, allow the plot of the Smith chart 800 torepresent possible impedances under different scenarios. Examples of thedifferent scenarios include: one or more receivers within a transmissionfield, one or more foreign objects in the transmission field, or anycombination of one or more receivers and one or more foreign objects inthe transmission field, location of the one or more receivers and/orforeign objects within the transmission field, other receiver specificinformation (e.g., device configurations/specifications, power requests,etc.), different configurations of the RF power transmitter device 100(e.g., hardware and/or firmware configurations), one or more poweramplifier power levels, and/or other scenarios described herein. Asmentioned above in reference to FIG. 7 , the different measurement setsfor different parametric parameters of the power amplifier are storedand used to determine the operational impedance of a power amplifierbefore and/or while RF energy is provided to a wireless-power receiver.A detailed explanation of the use of one or more plots of Smith chartsto produce the information stored in the LUTs is described below inFIGS. 9-13 .

In some embodiments, by obtaining different measurement sets for acombination of different parametric parameters from the variousmeasurements points depicted in FIG. 4 , the operational impedance forthe power amplifier can be determined (e.g., by comparing the value tothe LUTs or referencing the LUTs to predict the impedance). In someembodiments, when a condition to shut down the power amplifier isdetermined by using the stored values in the LUTs (e.g., the operationalimpedance cannot be made safe given the system's current operatingconditions), the power amplifier can be shut down immediately to preventdamage to the transmitter device (including the PA and other circuitry)and/or to the foreign object.

Various design aspects of the wireless power transmitting systemincluding the impedance detection and characterizing functions(including foreign object detection, receiver classification, and/orother scenarios reflected by detected impedance changes), such as thedimensions of the foreign object detection system, the dimension andconfiguration of the PAIC 161A (illustrated in FIGS. 4 and 5 ), thedimension of the antenna ground plane, size, shape, spacing, andarrangement of the two or more antenna arms, impedance and operatingfrequency of the antenna arms, and the configuration between the antennaground plane, and antenna arms, size and arrangement of the poweramplifiers are selected (e.g., optimized using a cost or performancefunction) for transmitting desired wireless wave characteristics.Wireless wave transmitting characteristics that vary based on the abovedesign aspects include, e.g., size, volume, materials, weight, cost,fabrication efficiency, radiation efficiency, impedance, and/orfrequency range (for transmission and/or reception of electromagneticwaves and other wireless waves by the antenna).

FIG. 9 illustrates a visual aid for describing impedance determinationsin accordance with some embodiments. In particular, FIG. 9 shows anexample mapping of measurement values for a combination of at least twoparametric parameters (determined based on values from at least some ofthe various measurement points) on a plot of a Smith chart to determine(e.g., predict) the operational impedance of the power amplifier, inaccordance with some embodiments. In particular, FIG. 9 shows acombination of measurement values (for at least two different parametricparameters) obtained from measurement points within the wireless-powertransmitter device 100 (as described with reference to FIG. 4 ) anddynamically obtained measurements (referred to as impedance measurementsherein) at a particular output power level of the power amplifier (e.g.26V).

As shown in FIG. 9 , the measurement values for the parametricparameters DC power 902 and power amplifier drain voltage 904 at a powerlevel 906 of 26V are plotted on a Smith chart. In some embodiments, themeasurement values for the parametric parameters DC power 902 and poweramplifier drain voltage 904 (as power), when plotted on the Smith chart,generate respective contours that are generally orthogonal to eachother. As described above, the orthogonal contours can be used todetermine valid (e.g, non-damaging) operating impedances of the poweramplifier. In particular, each intersection maps to an operatingimpedance, and the wireless-power transmitter device 100 determinesvalid and safe impedances (impedance thresholds) based on these contoursand/or intersections. Contours, or portions thereof, that do notintersect and/or intersect multiple times represent power conditionsthat do not map uniquely to valid impedances, and the wireless-powertransmitter device 100 determines invalid and unsafe impedances(impedances known to damage the power amplifier) based on these contoursand/or portions thereof. These valid and invalid operational impedancesare stored in the LUTs, in some embodiments, and used to determineoperational impedance at the power amplifier during operation.

In the example shown in FIG. 9 , contours for the measurement values forthe parametric parameters DC power 902 and PA drain voltage 904 (shownas power) at a power level 906 of 26V are plotted on a Smith chart andused to determine operational impedance at the power amplifier. Inparticular, FIG. 9 is a visual representation of the processes performedby the CPU (e.g., the RFIC 160 and or PAIC 161A). In some embodiments,during operation, the process includes using measurement values forparametric parameters stored in memory (within LUTs) as a baseline indetermining safe operation of the power amplifier (without plottingvalues on the Smith chart). Specifically, the LUTs can be used to selectthe appropriate power level or used as a reference point for dynamicallyobtained measurement points. FIG. 9 , as a visual aid in explaining theprocess, shows contours for stored measurement values for parametricparameters loaded from memory and plotted on a Smith chart and used as abaseline in determining safe operation of the power amplifier.

In some embodiments, one or more impedance measurements (908 a-908 d)from among multiple measurement points of the power amplifier areobtained dynamically (e.g., during operation, through periodic polling,and/or use of interrupts, etc.). For example, as depicted in FIG. 9 ,impedance measurements 908 a (m47) and 908 d (m83) correspond to theparametric parameter for PA drain voltage and impedance measurements 908b (m48) and 908 c (m49) correspond to the parametric parameter for DCpower, and each impedance measurement (908 a-908 d) is obtaineddynamically (or through periodic polling and/or use of interrupts) whilethe power amplifier is operating at a power level of 26V. In someembodiments, the one or more impedance measurements (908 a-908 d) areplotted along with the contours for the measurement values for theparametric parameters DC power 902 and PA drain voltage 904 at a powerlevel 906 of 26V to determine whether the operational impedances at thepower amplifier are within impedance thresholds.

Because each impedance measurement (908 a-908 d) maps to at least one ofthe contours, the wireless-power transmitter device 100 can determine(e.g., predict) that the operational impedance at the power amplifier iswithin the impedance thresholds for the power level (in this case, 26V).In other words, because the stored measurement values for parametricparameters obtained during simulation, characterization, and/ormanufacturing tests of the wireless-power transmitter device 100identify valid impedances of the power amplifier (and are used asinformation to populate the LUTs), the wireless-power transmitter device100 can determine (e.g., predict) that an operational impedance of thepower amplifier is within the impedance thresholds when the impedancemeasurements (908 a-908 d) are map to the LUTs (e.g., on and/or near anmeasurement values within the LUTs). In some embodiments, if animpedance measurement (908 a-908 d) does not map to the LUTs, thewireless-power transmitter device 100 determines that the operationalimpedance of the power amplifier is not within the impedance thresholdsand causes the power amplifier to select a new power level, shutdown,and/or perform other functions described herein.

Also shown in FIG. 9 are information blocks 910 a-910 d. In someembodiments, information blocks 910 a-910 d correspond to informationdetermined based on impedance measurements 908 a-908 d, respectively,and which can be used to determine the operational impedance and/or anumber of other values for the power amplifier. For instance, impedancemeasurements 908 a (m47) and 908 d (m83) for the parametric parameter PAdrain voltage 904 allow for determining information blocks 910 a and 910d, respectively. Information block 910 a indicates that the voltagedrain at impedance measurement 908 a (m47) is −12 W and the impedance atimpedance measurement 908 a (m47) is 48.97+j44. Information block 910 dindicates that the voltage drain at impedance measurement 908 d (m83) is−7 W and the impedance at impedance measurement 908 d (m83) is32.95-j54.29. Similarly, impedance measurements 908 b (m48) and 908 c(m49) for the parametric parameter DC power allow for determininginformation blocks 910 b and 910 c, respectively. Information block 910b indicates that the DC power at impedance measurement 908 b (m48) is 41W and the impedance at impedance measurement 908 b (m48) is 15.69-j1.87.Information block 910 c indicates that the DC power at impedancemeasurement 908 c (m49) is 49 W and the impedance at impedancemeasurement 908 c (m49) is 129.33-j4.22.

Although FIG. 9 shows contours for measurement values with parametricparameters for DC power 902 and PA drain voltage 904 (shown as power) ata power level 906 of 26V, different parametric parameters and/oroperating conditions (e.g., power levels, wireless-power transmitterdevice 100 configurations, etc.) can be used to determine operationalimpedances. As described above, different contours for measurementvalues (based on different parametric parameters) are known bysimulation, characterization (device and/or system), or manufacturingtest of the wireless-power transmitter device 100, learned through useof the wireless-power transmitter device 100, or other scenariosdescribed above. The information illustrated in the various informationblocks discussed above can be stored in the one or more LUTs describedherein.

FIGS. 10 and 11 are additional visual aids that illustrate differentuses of the impedance measurements in accordance with some embodiments.Similar to FIG. 9 , FIGS. 10-11 are visual representations of theprocesses performed by the CPU (e.g., the RFIC 160 and or PAIC 161A). Inoperation, the CPU does not necessarily plot values on one or more Smithcharts, but can reference LUTs as disclosed herein.

In FIG. 10 , different impedance measurements (1002 a-1002 e) (obtainedfrom measurement points within the wireless-power transmitter device100; as shown and discussed with reference to FIG. 4 ) are shown inrelation to antenna displacement from an optimal position (e.g. aposition directly on (or in front of) the antenna, or centered withinthe transmitted RF energy by the antenna). In other words, in FIG. 10the different impedance measurements (1002 a-1002 e) are obtained fordifferent locations from the optimal position (or location at which theRF energy is focused).

As shown by the Smith Chart, plotted impedance measurement values (1002a-1002 e) can be used to determine operational impedances, theoperational impedances varying by the distance between a receiver (orforeign object) and the optimal position. For instance, impedancemeasurement 1002 a (m46), as shown in information block 1004 a,corresponds to a 0 mm offset from the optimal antenna position (e.g., onthe antenna or directly centered on the transmitted RF energy by theantenna). The determined operational impedance for the impedancemeasurements 1002 a is 25.35-j25.31 at the optimal position. Impedancemeasurement 1002 b (m47), as shown in information block 1004 b,corresponds to a 5 mm offset from the optimal position (e.g., 5 mm fromthe antenna or 5 mm from the center of the transmitted RF energy by theantenna). The determined operational impedance for the impedancemeasurements 1002 b is 21.82-j24.49 at 5 mm away from the optimalposition. Impedance measurement 1002 c (m48), as shown in informationblock 1004 c, corresponds to a 15 mm offset from the optimal position.The determined operational impedance for the impedance measurements 1002c is 26.09-j2.71 at 15 mm away from the optimal position. Impedancemeasurement 1002 d (m49), as shown in information block 1004 d,corresponds to a 20 mm offset from the optimal position. The determinedoperational impedance for the impedance measurements 1002 d is64.35-j22.77 at 20 mm away from the optimal position. Impedancemeasurement 1002 e (m50), as shown in information block 1004 e,corresponds to a 25 mm offset from the optimal position. The determinedoperational impedance for the impedance measurements 1002 e is98.35+j49.64 at 25 mm away from the optimal position.

In some embodiments, a location of a receiver can be determined (e.g.,predicted) based on the impedance measurements (e.g., 1002 a-1002 e)and, optionally or alternatively, additional information provided by oneor more sensors of the wireless-power transmitter device 100. Inparticular, the one or more sensors can detect and/or classify areceiver and/or foreign object (in an operational zone) and provide theinformation to the wireless-power transmitter device 100 that alsoreceives impedance measurements. The wireless-power transmitter device100 uses the information from the one or more sensors and the impedancemeasurements (to perform lookups in the LUTs) to determine (or predict)the location of the receiver and/or foreign object). As shown in FIG. 10, different operational impedances for the different impedancemeasurement (e.g., 1002 a-1002 e) when plotted on a Smith chart show arelative a location of a receiver and/or foreign object form an optimalposition. In some embodiments, the wireless-power transmitter device 100can optimize performance based on the impedance measurement (e.g.,system power control loop implemented in firmware, power scaling asdescribed in FIGS. 12-13 , adjust of external circuit elements, etc.).In some other embodiments, the wireless-power transmitter device 100 canoptionally re-tune using external tuning components (as discussed abovewith reference to FIG. 4 ).

In FIG. 11 , the different impedance measurements (1002 a-1002 e; thesame impedance measurements as FIG. 10 ) are shown superimposed overcontours for measurement sets based on parametric parameters for DCpower 1102 and PA drain voltage 1104 at a power level 1106 of 26V. FIG.11 is used as a visual aid for the processes performed by the CPU (e.g.,the RFIC 160 and or PAIC 161A). The measurement sets for the parametricparameters DC power 1102 and PA drain voltage 1104 are plotted on aSmith chart (as described in FIG. 9 ). In some embodiments, VSWRthresholds, when plotted on the Smith chart, are represented as one ormore VSWR circles (e.g., 1108 a and 1108 b). In some embodiments, theone or more VSWR circles (e.g., 1108 a and 1108 b) include differentvalues (e.g., 1, 1.5, 2, 2.5, 3, etc.). In some embodiments, the VSWRcircles (e.g., 1108 a and 1108 b) can be used to visually indicatemismatch condition as discussed below (in operation the calculations areperformed be referencing LUTs and not by plotting).

In some embodiments, the one or more VSWR circles (e.g., 1108 a and 1108b) are used to verify the current status of the wireless-powertransmitter device 100. In particular, in some embodiments, the positionof the different impedance measurements (1002 a-1002 e) relative to theone or more VSWR circles (e.g., 1108 a and 1108 b) are used to verifythe status of the wireless-power transmitter device 100 (e.g., verifythat the power amplifier is operating at a safe power level). In someembodiments, impedance measurements within the one or more VSWR circles(e.g., 1108 a and 1108 b) indicate that the selected power levelsatisfies the VSWR thresholds and the power amplifier is operating at asafe level (e.g., the selected power level will not damage the poweramplifier). In some embodiments, impedance measurements outside of theone or more VSWR circles (e.g., 1108 a and 1108 b) indicate that theselected power level does not satisfy the VSWR thresholds and the poweramplifier may be operating at an unsafe level (e.g., the selected powerlevel could potentially damage the power amplifier). In someembodiments, when the impedance measurements do no satisfy the VSWRthresholds (e.g., circles 1108 a and 1108 b), the power dissipationvalues are verified to determine whether power scaling is necessary (asdescribed below in FIGS. 12 and 13 ). Alternatively or additionally, insome embodiments, when the impedance measurements do not satisfy theVSWR thresholds (e.g., circles 1108 a and 1108 b), software can re-tunethe system using external tuning components as described above withreference to FIG. 4 .

Determinations that the VSWR thresholds (or circles 1108 a and 1108 b)are satisfied, as described above, are performed by a processor (e.g.,RFIC 160 and/or PAIC 161A) using LUTs in memory 206. In particular, thewireless-power transmission system and/or methods described herein donot necessarily need to dynamically plot impedance measurements on Smithcharts in operation.

In some embodiments, information blocks 1110 a-1110 e correspond toinformation determined based on impedance measurements 1002 a-1002 e,and provide one or more values, such as the determined impedance at ameasurement point. Information blocks 1110 a-1110 e, are based on thesame measurements as in FIG. 10 (e.g., 1002 a-1002 e). It is noted, andas one of skill in the art will understand, that the slight differencesin the determined impedances between FIGS. 10 and 11 are due toartifacts of simulation in generating the Smith charts from theunderlying models/tests used to produce the data. The information blocksdiscussed with reference to FIGS. 10-11 can be stored in the one or moreLUTs.

FIGS. 12 and 13 are used as visual aids to describe power dissipationchecks and power scaling in accordance with some embodiments. In someembodiments, in accordance with a determination that impedancemeasurements do not satisfy the one or more VSWR thresholds (asdiscussed above), the power dissipation (based on measured values) isverified to determine whether power scaling is necessary. FIGS. 12 and13 show example mappings of measurement values for a combination of theparametric parameters (i) output voltage of the power amplifier 1202,and (ii) the dissipated power 1204 at a power level 1206 of 26V, whichare plotted on a Smith chart (e.g., generating contours for the outputvoltage 1202, and the dissipated power 1204 as described above withreference to FIG. 8 ).

FIG. 12 shows a mapping of impedance measurements (1208 a-1208 e) on aplot of the Smith chart with contours for the measurement values forparametric parameters for the output voltage 1202, and the dissipatedpower 1204 that can be used to check the power dissipation at the poweramplifier at a power level 1206 of 26V, in accordance with someembodiments. In some embodiments, the wireless-power transmitter device100 has a power dissipation limit for the power amplifier (or a powerhanding limit for the power amplifier to provide safe operation). Insome embodiments, the power dissipation limit is 10 W, 15 W, 20 W, orother values defined by at least the power amplifier (other potentialcontributing factors the dissipation limit include temperature, the sizeof the enclosure/housing, and other factors). In some embodiments, thedissipation limit includes a tolerance of +/−1.5 W. As mentioned above,the power dissipation limit (or threshold) is determined duringsimulation, characterization, and/or manufacturing tests of thewireless-power transmitter device 100 and stored in memory 206.

In some embodiments, the impedance measurements (1208 a-1208 e), whenplotted with the measurement value contours for the parametricparameters output voltage 1202 and the dissipated power 1204, can beused to determine a power dissipation of the power amplifier. The LUTsin memory 206 include different power dissipation thresholds that thepower amplifier can safely tolerate while operating at different outputpower levels, and/or configurations of the wireless power transmissionsystem. Thus, the system can retrieve a respective power dissipationlimit by performing a lookup in the LUTs using the current output powerlevel of the PA and other information (such as the measurements from themeasurement points, operational impedance for the PA, and otherconfiguration information (such as number of receivers in the operatingarea, operating frequency)).

In some embodiments, when an impedance measurement (e.g., 1208 a-1208 e)is determined to exceed the power dissipation limit, the wireless-powertransmitted may initiate power scaling as described further below inFIG. 13 . In the example shown in FIG. 12 , the power amplifier of thewireless-power transmitter device 100 has a power dissipation limit of15 W. In this example, three impedance measurements shown in FIG. 12 ,m76 1208 a; m77 1208 b; and m78 1208 c, correspond to the dissipatedpower 1204 parametric parameter, and are used to determine the powerdissipation of the power amplifier. As shown, the information blocks1210 a, 1210 b, and 1210 c, determined based on the impedancemeasurements 1208 a-1208 c, respectively, show that the powerdissipation is 2 W at m76 1208 a, 11 W at m77 1208 b, and 20.87 W at m781208 c. In the current example, in accordance with a determination thatm78 1208 c has a power dissipation greater than the power dissipationlimit (in this example 15 W), the wireless-power transmitter device 100initiates power scaling (power scaling is described more below).Impedance measurements 1208 d and 1208 e correspond to the outputvoltage 1202 parametric parameter, and are used to determine the outputvoltage of the power amplifier as shown information blocks 1210 d and1210 e, respectively. In some embodiments, the impedances for eachimpedance measurement 1208 a-1208 e, as shown in information blocks 1210a-1210 e, can be checked to ensure that they are within a safeoperational threshold as described above. In some embodiments, if noimpedance measurement has a determined power dissipation above thedissipation limit, the wireless-power transmitter device 100 forgoespower scaling.

FIG. 13 illustrates a visual aid for describing power scaling inaccordance with some embodiments. FIG. 13 shows a mapping of impedancemeasurements (1308 a-1308 e) on the Smith chart with contours for theparametric parameters output voltage 1202, and dissipated power 1204 ata power level 1306 of 16V (a lower power level that satisfies the powerdissipation limit; as discussed below). As discussed above in referenceto FIGS. 7-12 , the one or more contours are specific to one or morepower levels and/or other configurations (determined during simulation,characterization, and/or manufacturing test of the wireless-powertransmitter device 100). After changes to the power level (or otherconfigurations) are made, the wireless-power transmitter device 100 usesthe respective measurement values for the new power level. For example,in FIG. 13 , after changes to the power level (or other configurations)are made, contours for the new power level (16 V) are loaded onto a plotof the Smith chart (as can be seen in the updated Smith charts of FIG.13 ). In this same manner, the wireless-power transmission systemdescribed herein uses a respective LUTs or LUTs values for the adjustedconfiguration.

Returning to the power scaling implementation, as described above inFIG. 12 , when it is determined that the power dissipation for animpedance measurement (e.g., 1208 c in FIG. 12 ) is greater than thepower dissipation limit (in the above example, 15 W), the wireless-powertransmitter device 100 performs power scaling (e.g., power dissipationdetermined by referencing the impedance value 1208 c within a LUT inmemory 206 to determine a dissipation for the current power level). Insome embodiments, power scaling includes selecting a new power levellower than the power level that is determined to exceed the powerdissipation limit, and then checking to ensure that the new power levelsatisfies the power dissipation limit. In some embodiments, afterdetermining that the new power level does satisfy the power dissipationlimit, the wireless-power transmitter device 100 performs receiverclassification and/or optionally re-tunes (as described above), and thenincreases the power provided to the power amplifier until a maximum isreached for the current configuration (a maximum power level thatsatisfies all of the one or more safety thresholds and is within thepower dissipation limit). In some embodiments, after determining thatthe selected power level does not satisfy the power dissipation limit,the wireless-power transmitter device 100 selects a new power level orinstructs the power amplifier to shut down.

For example, as shown between FIG. 12 and FIG. 13 , at a first time, thepower amplifier is at a first power level 1206 of 26V, and thedetermined power dissipation of m78 1208 c is greater than the powerdissipation limit (15 W in this example). At a second time (FIG. 13 ),in order to protect the power amplifier, power scaling is performed andthe wireless-power transmitter device 100 selects a second power level1306 of 16V for the power amplifier. At the second power level 1306, thedetermined power dissipation of m78 1308 c has dropped to 11 W (as shownin information block 1310 c of 13) and is within the power dissipationlimit of 15 W for this example. The wireless-power transmitter device100 further checks that the impedance measurement 1308 a-1308 e satisfythe one or more safety thresholds. As is shown in information blocks1310 a-1310 e, the impedance measurement 1308 a-1308 e can be used todetermine the impedance and a number of other values for the poweramplifier using the Smith charts. As indicated above, FIGS. 12 and 13are intended as visual aids and the wireless-power transmissiondisclosed herein does not necessarily plot one or more values on a Smithchart, but references one or more LUTs in memory that include storedvalues for different power levels, the operational scenarios, and/orconfiguration of the wireless power transmission system. Thewireless-power transmission system disclosed herein uses the one or moreLUTs in memory to perform power scaling as described herein.

Although FIGS. 9-13 illustrate a power amplifier at a power level of 26Vor 16V, it should be noted that different power levels, if available tothe power amplifier, can be selected. It should also be noted that whileFIGS. 9-13 show impedance measurements at a single point in time, inoperation, the wireless-power transmitted 100 dynamically monitors andevaluates the impedance measurements for classifying a receiver,detecting movement of a receiver and/or foreign object, determining anRF signal, and/or determinations described above. In some otherembodiments, the wireless-power transmitted 100 may periodically pollthe measurements points to perform the above-described determinations.

The descriptions of FIGS. 9-13 are made in reference to visualrepresentation of one or more parametric parameters and/or impedancemeasurements plotted on one or more Smith charts; however, one personskilled in the art, upon reading the present disclosure, will appreciatethat the one or more parametric parameters and/or impedance measurementsplotted on one or more Smith charts can be stored in LUTs in memory 206of the wireless-power transmitter device 100 (e.g., as described in FIG.2A). For example, stored values can be accessed in memory 206 and usedby one or more modules, such as the impedance determining module 223, toperform the techniques described above in FIGS. 9-13 (e.g., withoutvisually plotting the Smith charts).

Similarly, one skilled in the art will appreciate that impedancemeasurements obtained in real-time (e.g., during operation) can be usedto perform the techniques described above. In other words, impedancemeasurements obtained in real-time can be used by one or more modules,such as the impedance determining module 223, to perform the techniquesdescribed above in FIGS. 9-13 (e.g., without visually plotting the Smithcharts).

Further, the techniques described above can be performed dynamically andin real time.

As described above, LUTs are a data structure stored in memory thatinclude values that can be referenced. In reference to the examplesprovided above in FIGS. 7-13 , LUTs can include impedance valuescollected from different measurement points at different power levels,operational scenarios, transmitter device 100 configurations. The LUTscan also include the operational impedances, VSWR determinations (e.g.measured values and thresholds), power dissipation determinations (e.g.measured values and thresholds), and/or other values described hereinbased on the combination of two or more impedance values. In operation,the impedance value obtained from the one or more measurement points canbe used to reference the values in the LUTs and determine an expected orknown result that has been predefined for the transmission device. Itshould be noted, the LUTs include similar reference tables for SAR,e-field roll-off, and/or other safety thresholds disclosed herein.

Conventional ways to protect power amplifiers, such as through isolatorsor by using measurements of forward and reflected power, have certaindrawbacks that are addressed by the techniques discussed herein. Forinstance, use of isolators can be bulky and it adds to the total cost tothe wireless power transmission system. The efficiency of the wirelesspower transmission also decreases because of the additional loss causedby the isolator.

Also, methods using directional couplers typically cannot be used tofind the impedance at the output of the power amplifier. The directionalcoupler can be bulky and it adds to the total cost to the wireless powertransmission system. The efficiency of the wireless power transmissionalso decreases because of the additional loss caused by the directionalcoupler.

Another technique is Q detection method, but these Q detection methodscan only be done in advance of charging. In addition, each receiverneeds to store its own “expected values” for time domain decay orfrequency response.

In another example, power balance method is used to protect the poweramplifier of a wireless-power transmitter device 100. In the powerbalance method, losses are continuously monitored during charging. Ifthe losses detected is greater than a predetermined threshold, a foreignobject may be present in proximity to the antenna of the transmitter.However, the determination of the presence of the foreign object can befooled by load transients and/or receiver motion. In addition, it takestime to calculate steady state losses, during that time foreign objectand/or the power amplifier could be heated or damaged.

In another example, in band communications method is used to protect thepower amplifier of a wireless-power transmitter device 100. In the inband communications method, a transmitter sends queries out. A receiverdevice sends back an acknowledgement signal once it receives the queryfrom the transmitter. In that case, a transmitter only transmit wirelesspower waves to receivers which sends back the acknowledgement. Thismethod requires more complex receiver device to implement thecommunications protocol. However, this method does not work if a validreceiver has little influence on the transmitter impedance (e.g. in thenearfield or midfield range).

Compared to the above several methods of protecting the power amplifiers(e.g., isolator and/or directional coupler), the present disclosureprovides an impedance-based method for protecting power amplifiers thathas many advantages (e.g., impedance detection method described inreference to at least FIGS. 9-13 ). For example, in the impedance-basedmethod, no handshaking protocol is required. Therefore, no complexreceiver-side components are necessary to implement the communicationprotocol. In addition, the impedance-based method enables continuousoperation during charging which prevents damages to the transmitterand/or to the foreign object when the system is waiting to calculateloss. The continuous operation also provides instant responds to thepresence of the foreign objects especially when there is a change in therelative positions of the wireless-power transmitter device 100 andwireless power receiver.

In some embodiments, the wireless-power transmitter device 100 is astandalone device. In some embodiments, the wireless-power transmitterdevice 100 is integrated with or included within an electronic deviceenclosure such as that of a television, a display, a laptop, a gamingsystem or video player, television set top box or similar device, or acellphone, etc. In some embodiments, the wireless-power transmitterdevice 100 is a device 1400 (e.g., such as a smart speaker). FIG. 14A isan isometric illustration of the device 1400 with an includedwireless-power transmitter device 100, according to some embodiments. Insome embodiments, the device 1400 is similar in shape to the embodimentdepicted in FIG. 14A. In some embodiments, the device 1400 is capable ofcharging up to two client devices with incorporated receivers within itscharging coverage area. In some embodiments, the device 1400 is capableof charging up to four client devices with incorporated receivers withinits charging coverage area. In some embodiments, the device 1400 iscapable of charging multiple client devices with incorporated receiverswithin its charging coverage area.

FIG. 14B is a top view of the device 1400 (e.g., an electronic devicesuch as a smart speaker) with an included wireless-power transmitterdevice 100 and its charging coverage area 1402 (e.g., which can be aninstance of antenna coverage area(s) 290 and/or 291 described above),according to some embodiments. As an illustrative example the device1400 is depicted as a smart speaker, and will thus be referred to inthese examples as a device 1400. In some embodiments, the chargingcoverage area 1402 is a space directly in front of the device's 1400transmitter. In some embodiments, the charging coverage area 1402 is nogreater than 15 cm to the front of the device 1400. In some embodiments,the charging coverage area 1402 is no greater than 30 cm to the front ofthe device 1400. In some embodiments, the charging coverage area 1402 isno greater than 1 meter to the front of the device 1400. In someembodiments, the charging coverage area 1402 has a shape of a portion ofan oval extended from the front face 1404 of the device 1400.

Alternatively or additionally, in some embodiments, the device 1400 isconfigured to transmit (e.g., radiate) RF energy at a location of thewireless-power receiver. In some embodiments, the radiated RF energy isbased on an amplified RF signal provided to one or more antennas of thedevice 1400 from the power amplifier. The amplified RF signal, whenreceived by the one or more antennas, cause the one or more antennas toradiate the RF energy. The radiated RF energy is focused within anoperating area that includes the wireless-power receiver while forgoingany active beamforming control (e.g., the wireless-power transmitterdevice 100 does not modify the phase, gain, etc. of the radiated RFenergy for beamforming purposes). Focused within an operating area thatincludes the wireless-power receiver, in some embodiments, means that apeak level of RF energy is at its maximum at the location of thewireless-power receiver. The RF energy is transmitted by the device 1400in accordance with a determination (e.g., a prediction) thattransmitting the RF signal to the wireless-power receiver would satisfyone or more safety thresholds as discussed herein.

In some embodiments, a determination that the RF energy to thewireless-power receiver would satisfy the one or more safety thresholdsis made before any RF energy is transmitted to the wireless-powerreceiver. In this way, the device 1400 (or any other wireless-powertransmitter device 100 that includes the embodiments disclosed herein)ensures that an appropriate power level of the available power levels isselected for use in amplifying the RF signal, such that the one or moresafety thresholds will still be satisfied after the RF signal istransmitted.

FIG. 14C is a side view of the device with the included device 1400 andits charging coverage area 1402, according to some embodiments. In someembodiments, a client device 1406 coupled with a wireless-power receiveris placed within the charging coverage area 1402 to receivewireless-power transmitted from the device 1400. In some embodiments,the client device 1406 is placed on a flat surface such as a table or afloor. In some embodiments, the client device 1406 is a small consumerdevice, such as a fitness band or a watch wearable product. Additionalexamples of a consumer device include a phone, a tablet, a laptop, ahearing aid, smart glasses, headphones, computer accessories (e.g.,mouse, keyboard, remote speakers), and/or other electrical devices.

In one embodiment, the device 1400 has dimensions at 7 cm tall×4 cmdeep×15 cm long. In some embodiments, the device contains one antenna.The antenna is configured to generate and use locally RF energy at 917.5MHz. The antenna is enabled to transmit energy only when an authorizedclient device 1406 has been determined to be in the charging coveragearea 1402.

In some embodiments, the device 1400 and client devices 1406 usecommunication components, such as standard Bluetooth low energy (“BLE”)communications paths operating at 2.4 GHz, to enable the device 1400 tomonitor and track the location of the client devices 1406. The locationof the client devices 1406 is monitored and tracked based on thecharging information receives from the client devices 1406. As discussedabove in FIGS. 1A and 2A the charging information can include thelocation of the wireless-power receiver, whether the wireless-powerreceiver is authorized, charge requests, and/or other receiver specificinformation.

In some embodiments, the device 1400 uses the charging information toselect and use a power level and instruct the power amplifier to amplifyRF signals. In some embodiments, instead of determining that all of theone or more safety thresholds are satisfied, the RF power transmitterdevice 100 uses the charging information to select a power level of thepower amplifier that is at or within the global maximum and globalminimum power levels for the power amplifier (identified in the one ormore safety thresholds) before providing the client device 1406 with therequested power (e.g., satisfying only the global max and min safetythresholds). For example, in some embodiments, the power level can beselected based on the charging information alone. In some embodiments,the device 1400 uses the charging information in conjunction with theother methods disclosed herein to determine that all or a subset (lessthan all) of the one or more safety thresholds (e.g., satisfaction SARvalues, impedance measurements, roll-off, etc.) are satisfied before RFenergy is transmitted to the client device 1406.

In some embodiments, the device 1400 can transmit power to the clientdevice 1406 without receiving any charging information (e.g., when theRF power transmitter and/or receiver do not have a communicationscomponent). For example, the device 1400 can identify and classify areceiver and/or foreign object, determine an appropriate power level totransmit RF energy, and safely transmit the RF energy to the clientdevice using impedance determinations (e.g., detected changes inimpedance) and/or other methods described above. In some otherembodiments, power is transmitted only when a client device 1406 ispresent, requests charging, and is authorized to receive power. In otherwords, in some embodiments, the device 1400 transmits power to a clientdevice 1406 only when charging information (that includes a request forpower) is received from the client device 1406. The device 1400 cancombine each of the methods disclosed herein to provide power to theclient device 1406.

In some embodiments, the device 1400 is used on top of a householdsurface. In some embodiment, the device 1400 is configured to chargemultiple low-power devices. Table 1 below summarizes example technicalcharacteristics of the device 1400, according to some embodiments.

TABLE 1 Example Technical Characteristics of the Device 1400. TargetPlatforms “Smart Speaker” charging system Wireless Power Transfer 917.5MHz Frequency Antenna Type Loop Antenna Gain  7 dBi Max Tx-Rx Distance30 cm Transmitter Size L = 15 cm, H = 7 cm, W = 4 cm, Number ofantenna’s 1 Conducted Output Power 39 dBm Receiver application Fitnessband, other small wearables Simultaneous Rx Yes Number Receivers 4Supported BLE for Tx/Rx Yes Sensor Required for Yes SAR Compliance

FIG. 14D is an overhead view of a “keep out zone” and operational area(or working zone) of a device 1400 with a wireless-power transmitter inaccordance with some embodiments. In some embodiments, the device 1400includes one or more sensors 1408. In some embodiments, the one orsensors are the same type of sensor. In some embodiments, the one orsensors are different types of sensors. In some embodiments, differentcombinations of similar and different types of sensors are used. In someembodiments, the one or more sensors 1408 includes a first sensor 1408 aand second sensor 1408 b. In some embodiments, one or more sensors 1408are located in at one or more corners, the top center, the bottomcenter, directly in the center, on one or more of the edges, and/or anyother position of the device 1400 such that the keep-out zone and/oroperational area can be monitored. The one or more sensors can includeinfrared (IR) sensors, heat detectors, capacitive sensors, inductivesensors, hall sensors, proximity sensors, sound sensors, pressuredetectors, light and/or image sensors, and/or other types of sensors.

In some embodiments, a first sensor 1408 a is located at a first cornerand/or side of the device 1400 and a second sensor 1408 b is located ata second corner and/or side of the device 1400, the second corner and/orside opposite the first corner and/or side. In this example, the firstsensor 1408 a covers and/or monitors a first region 1410 a and thesecond sensor 1408 b covers and/or monitors a second region 1410 b. Insome embodiments, the first 1410 a and the second 1410 b regions coverand/or monitor an area directly in front of the device 1400.Additionally or alternatively, the first 1410 a and the second 1410 bregions cover and/or monitor areas within the transmission field of thedevice 1400. In some embodiments, the first 1410 a and the second 1410 bregions generate a “keep out zone” or shut-off distance 1412. In someembodiments, the shut-off distance 1412, is an area and/or spacedirectly in front of the device's 1400 antenna. In some embodiments, theshut-off distance 1412 includes a predetermined distance “d_s” is nogreater than 10 cm (+/−2 cm) from the front center of the device 1400.In some embodiments, the predetermined distance d_s is no greater than15 cm (+/−2 cm) from the front center of the device 1400. In someembodiments, the predetermined distance d_s is no greater than 20 cm(+/−2 cm) from the front center of the device 1400. In some embodiments,the shut-off distance 1412 covers an entire front surface of the device1400. In some embodiments, the predetermined distance extends radiallyfrom a center point of the device 1400, such as is depicted in FIG. 14D.

In some embodiments, the one or more sensors 1408 provide an indication(shut-off indication) that an object is within the shut-off distance1412 of the device 1400. In some embodiments, the object includes aforeign object that is detected by the system using the techniquesdescribed herein. In some embodiments, in response to receiving theshut-off indication, the device 1400 causes (e.g., via the RFIC 160and/or the PAIC 161A) the one or more antennas to cease radiating the RFenergy. In particular, in some embodiments, the device 1400 is shut offwhen a person or animal (or some other sensitive object or a foreignobject) is detected within a predefined shut-off distance 1412(semi-circle in FIGS. 14D and 14E). The device 1400 is shut off to avoidexposing any sensitive objects to the electromagnetic energy (RFenergy), e.g., because a power level of the electromagnetic energy inthe shut-off distance 1412 is higher than a power level of theelectromagnetic energy in other regions and/or locations of the chargingcoverage area 1402.

In some embodiments, the one or more sensors 1408 cover and/or monitor asecond region (the second region referred to as the operation area1413). In some embodiments, the operational area 1413 covers and/ormonitors an area directly in front of the device 1400. In someembodiments, the operational area 1413 is an area and/or space directlyin front of the device's 1400 antenna. In some embodiments, theoperational area 1413 includes a predetermined distance “d_o” that is nogreater than 2 m (+/−0.2 m) from the front center of the device 1400. Insome embodiments, the predetermined distance do is no greater than 1.5 m(+/−0.2 m) from the front center of the device 1400. In someembodiments, the predetermined distance d_o is no greater than 1 m(+/−0.2 m) from the front center of the device 1400. In someembodiments, the operational area 1413 covers an entire front surface ofthe device 1400. In some embodiments, the predetermined distance extendsradially from a center point of the device 1400, such as is depicted inFIG. 14D.

In some embodiments, the one or more sensors 1408 provide an indication(e.g., detection and/or classification indications) that a receiverand/or foreign object is within the operational area 1413 of the device1400. In some embodiments, the receiver and/or foreign object isdetected and/or classified by the system using the techniques describedherein. In some embodiments, in response to receiving the indication,the device 1400 causes (e.g., via the RFIC 160 and/or the PAIC 161A) theone or more antennas to select a power level, optimize the powertransmission, tune (dynamically or statically) one or more antennas,adjust the radiation profile, and/or perform other adjustments disclosedherein. In particular, in some embodiments, the device 1400 will performthe operations disclosed herein when a receiver and/or foreign object isdetected within a predefined operational area 1413 (semi-circle in FIGS.14D and 14E).

FIG. 14E is another overhead view of a device 1400 with a wireless-powertransmitter illustrating a charging coverage area, operating zone, and“keep out zone” in accordance with some embodiments. In someembodiments, the device 1400 includes a shut-off distance 1412 (e.g.,d_s) as described above in 14D. In some embodiments, the device 1400includes a charging coverage area 1402 (also referred to as transmissionfield) that is a space directly in front of the device's antenna. Insome embodiments, the charging coverage area 1402 covers a distanceequal to the operating area 1413 (e.g., d_o). In some embodiments, thecharging coverage area 1402 covers a distance described above in FIG.14C (e.g., no greater than 1 meter). In some embodiments, the chargingcoverage area 1402 extends a predetermined angle (e.g., angle theta (θ))1414 in each direction from the center line 1416. In some embodiments,the predetermined angle 1414 is at least 60 degrees in each directionfrom the center line 1416. In some embodiments, the predetermined angle1414 is at least 75 degrees in each direction from the center line 1416.In some embodiments, the predetermined angle 1414 is at least 80 degreesin each direction from the center line 1416.

In some embodiments, the device 1400, via the RFIC 160 and/or PAIC 161A,can control and/or manage operation of one or more power amplifiers tooptimize the performance of the one or more antennas. In someembodiments, the RFIC 160 and/or PAIC 161A dynamically adjust powerdistribution for a transmission field of the antenna provided to awireless-power receiver (e.g., based on predetermined properties and/orcharacteristics of the wireless-power transmission system obtainedduring simulation, characterization, and/or manufacture tests of thewireless-power transmitter device and/or one or more antennas of thetransmitter device stored in the LUTs). For example, as shown in FIG.14E, charging area 1402 can be adjusted by the RFIC 160 and/or PAIC 161Ato improve the charging area, as shown by improved charging area 1418(or improved transmission field). In some embodiments, dynamicallyadjusting the power distribution to improve the transmission fieldincludes, at the RFIC 160 and/or PAIC 161A, adjusting the power providedto the one or more antennas from the one or more power amplifiers. Insome embodiments, the power distribution for the transmission field isadjusted (e.g., from charging area 1402 to improved charging area 1418)based on the adjusted power provided to the antenna from the poweramplifier. In some embodiments, the power distribution for thetransmission field is adjusted such that the adjusted power provided tothe one or more antennas is evenly distributed across the powerdistribution for the transmission field; and a power loss at an edge ofthe power distribution for the transmission field of the antenna isreduced from 30% to 10%. For example, improved charging area 1418 hasthe power distribution at the edges improved by distance L 1420(representative of an improvement at the edges from a reduction of 30%to 10%). Improved charging area 1418 also shows that the distribution iseven, maintaining its radial shape.

The optimization of the antenna described in FIG. 14E is performedwithout beamforming (or by forgoing beamforming) and produces thedescribed improvements through precise control of the power amplifiervia the RFIC 160 and/or PAIC 161A (based on LUTs in memory 206 asdescribed above).

As described above with reference to FIGS. 14A-14E, the device 1400 caninclude a single antenna (e.g., a loop antenna) and a single poweramplifier. In some embodiments, the device 1400 may include more thanone antenna and/or power amplifier. In some embodiments, the one or moreantennas can be any antenna type, as indicated above.

FIG. 15A is an exploded view of a device with an included wireless-powertransmitter, according to some embodiments. In some embodiments, thedevice 1400 includes components such as a front cover (enclosure) 1502,a loop antenna 1504, an antenna mount 1506, one or more sensors 1508, aground plane 1510, a control printed circuit board (PCB) 1512, a PCBshield or heatsink 1514, and an enclosure housing 1516. In someembodiments, the loop antenna 1504 is similar as the loop antenna 300described in FIG. 3 . In some embodiments, the loop antenna 1504 onlyincludes one feed 304 as described in FIG. 3 . Alternatively oradditionally, in some embodiments, the device 1400 includes any antennatype described above in FIGS. 1A-1C. In some embodiments, the one ormore sensors 1508 are integrated or placed on the ground plane 1510. Insome embodiments, although not shown, additional sensors of one or moresensors (not shown) are located exterior to the device 1400 and/or nearthe front cover 1502 (e.g. along the edges, the corners directly in thecenter of device 1400 and/or the front cover 1502). In some embodiments,the other set of one or more sensors (not shown) is configured to definethe “keep out zone” (e.g., shut-off distance 1412) and the operationalarea 1413 of the device 1400. In some embodiments, the front cover(enclosure) 1502 is made of plastic. In some embodiments, the antennamount 1506 is made of plastic. In some embodiments, the enclosurehousing 1516 is made of plastic.

In some embodiments, the device 1400 includes a single antenna 1504. Insome embodiments, the antenna 1504 has a rectangular aperture that isapproximately 2 inches by 6 inches and 10 mm thick formed as a loopbacked by a PCB 1512 and/or a ground plane 1510 as a reflector. In someother embodiments, the device 1400 multiple antennas, the multipleantennas consisting of one or more types described above in FIGS. 1A-1C.The multiple antennas can be of any dimensions that fit the device's1400 dimension and/or generate the desired frequencies and/orperformance.

The mechanical illustrations are further depicted in FIGS. 15B and 15C.FIG. 15B is a side cross-sectional view illustration of a device 1400with an included wireless-power transmitter, according to someembodiments. In some embodiments, the loop antenna 1504 is placed veryclose to the front surface 1518 or front cover (enclosure) 1502 of thedevice 1400. The loop antenna 1504 is placed on the antenna mount 1506.A PCB shield or heatsink 1514 is covered on the control PCB 1512.

FIG. 15C is a transparent illustration of an assembled device with anincluded wireless-power transmitter, according to some embodiments. Theloop antenna 1504 can be viewed from the transparent side view.

FIGS. 16 and 17 illustrate power density level decays (or roll-offs) ofthe transmitted RF energy relative to a location of a wireless powerreceiver and/or a location of a peak power level, according to someembodiments.

In some embodiments, governing regulations can require that: (i) thereceiver's location reside within a predefined radial distance (e.g.,m*λ) from the local peak power level (P¹) (e.g., focused RF energy atthe location of the receiver), and (ii) the power, relative to the peakpower level (P¹), decays by at least k dB at the predefined radialdistance (e.g., m*λ) in all directions from the local peak power level(P¹) to a decayed peak power level (P²) (e.g., in all sphericaldimensions/directions from the peak power level (P¹)). Further, in someinstances, future regulations may require some power decrease relativeto the local peak power level (P¹) at a point closer to the one or moreantennas (i.e., a local minimum power level is required near the one ormore antennas). Additionally, in some instances, the regulations canrequire that a magnitude (e.g., measured dB) of the local peak powerlevel (P¹) is below some predefined threshold. The following equationmay represent the required power decay at the predefined radialdistance:

P ² =P ¹ −k dB

where k is a number ranging from approximately 1 dB to 6 dB (althoughthese values may change depending on a size and power delivered by theone or more antennas).

In some embodiments, the wireless-power transmitter (e.g., device 1400)is able to determine (e.g., predict) an RF signal that, when amplifiedby a power transmitter and provided to the one or more antennas, causesthe one or more antennas to radiate RF energy focused within anoperating area that includes the wireless power receiver that inconfigured to decay (e.g. roll-off) a predetermined amount for eachpredetermined distance increment from the relative peak power of the RFenergy produced by radiated RF energy. In some embodiments, the one ormore wireless-power-transmission safety criteria include thepredetermined roll-off (e.g. 3 dB) at each predetermined distanceincrement (e.g., 8 cm) relative to a peak amount of RF energy producedby radiated RF energy. In some embodiments, the determination thattransmitting the RF signal would satisfy the one or more safetythresholds is made when it is determined that transmitting the RF signalwould create a peak amount of RF energy at the wireless-power receiverthat has the predetermined roll-off for each predetermined distanceincrement relative to the peak amount of RF energy. In some embodiments,the determination is made by the RFIC 160 and/or the PAIC 161A of thewireless-power transmitter.

In some embodiments, the predetermined distance increment is apredefined radial distance defined as 1λ. However, the predefined radialdistance may be other values, such as 0.5λ, 1.5λ, 2λ, etc., or may bedefined relative to a range of values such as between 0.5λ to 2.5λ,between 0.5λ-1.5λ, between 0.75λ to 1λ, etc. In some embodiments, thepredefined radial distance is not defined relative to a wavelength (“λ”)and is instead defined using a unit of length, such as feet, such thatthe predefined radial distance may 0.5 feet, 1.5 feet, 2 feet, or someother appropriate value.

In some embodiments, the local peak power level (P¹) is configured toroll-off by a predetermined amount to a decayed peak power level (P²).In some embodiments, the location of the peak power level (P¹) is at thelocation near and/or at the wireless-power receiver, the wireless-powerreceiver residing within one wavelength (1λ) from the location of thepeak power level (P¹). As described above, in some embodiments, the peakpower level (P¹) decays by a predetermined roll-off to a decayed peakpower level (P²). The predetermined roll-off decays the peak power level(P¹) at least k dB at a predetermined distance increment of 1λ from thelocation of the peak power level (P¹).

In some embodiments, the predetermined distance increment is apredefined radial distance is 1λ and the required drop off from the peakpower is 3 dB (the “example power-focusing regulations”). In someembodiments, the predefined radial distance and the required drop offmay be configured to include less restrictive values (e.g., thepredefined radial distance is less than 1λ and the required drop off is1 dB) or may have more restrictive values (e.g., the predefined radialdistance is greater than 1λ and the required drop off is 4 or 5 dB).

FIG. 16 illustrates an example of the RF energy focused within anoperating area that includes the location of a wireless-power receiverdecaying or rolling-off by a predetermined amount at a predetermineddistance increment from the peak amount of RF energy, in accordance withsome embodiments. As shown in FIG. 16 , the wireless power transmitter(e.g. device 1400) can model, via the RFIC 160 and/or PAIC 161A, whatpeak amount of RF energy will be produced at the wireless-powerreceiver, and then determine (e.g. predict) whether a safety thresholdof a predetermined roll-off of 3 dB is going to be satisfied, e.g., thatat the radiated RF energy will roll-off by a predetermined amount (e.g.,3 dB) at a predetermined distance increment (e.g., 8 cm) from the peakpower level of the RF energy. While the primary example given here forillustrative purposes is a predetermined 3 dB roll-off value and apredetermined distance increment of 8 cm, in some embodiments, othersuitable predetermined roll-off values and predetermined distanceincrements can be utilized as described above.

As shown in FIG. 16 , RF energy is focused within an operating area thatincludes the location of a receiver 104 of a client device 1406. The RFenergy focused within an operating area that includes the receiver 104generates a peak power level (P¹) 1602 at and/or near the location ofthe receiver 104. In some embodiments, the device 1400, via the RFIC 160and/or the PAIC 161A, selects an RF signal that, when provide by thepower amplifier to one or more antennas of the device 1400, causes theRF energy to roll off by a predetermined roll-off (e.g. 3 dB) at apredetermined distance increment 1604 (e.g. 8 cm) from the peak powerlevel (P¹) 1602, such that the decayed peak power level (P²) 1606(located at the predetermined distance increment from the peak powerlevel (P¹) 1602) is equal to the peak power level (P¹) 1602 decreased bythe predetermined roll-off (e.g., P²=P¹−k dB).

FIG. 17 is another illustration of a measured electric field plot 1702and 2D graph 1704 to demonstrate electric field (E-field) roll-off below10 dB from a peak value at about 3 dB for about every 8 cm for a device1400 with an included wireless-power transmitter, according to someembodiments. In some embodiments, the E-field is measured by an electricfield measurement setup for a device 1400 with an includedwireless-power transmitter. In some embodiments, an electrical fieldplot was taken to capture the E-Field value at the center point 1706 ofthe antenna of the device 1400 and to evaluate the power roll-off todetermine that the RF energy is locally used. The measurement locations,E-Field values and roll-off are shown in FIG. 17 . In some embodiments,the RF energy is focused within an operating area that includes thecenter point 1706 of the antenna of the device 1400 and at a distance of5 cm away from the front face of the device 1400, the measured E-Fieldvalue is 174.5V/m at a degradation of 44.84 dBV/m. In some embodiments,on average, for about every 8 cm, the E-field rolls off about 3 dB. Insome embodiments, “about 8 cm” refers to +/−0.5 cm of 8 cm, so the rangewould be between 7.5-8.5 cm. At a distance of 40 cm away from the frontface of the device, the E-Field compared with the E-Field value at 5 cmaway is −15 dB. The 2D plot 1704 also shows that the E-Field and thepower emitted from the antenna of the device 1400 is contained in alocal area with a decreased dB values from the position 1706 at 5 cmaway.

In some embodiments, while at an E-Field value of 174.5V/m, the SARvalue should not exceed the FCC 1.6 W/kg limitation requirement. In someembodiments, when a distance to the face of the device 1400 is short,such as less than 5 cm, one or more sensors will be used to manage a“keep out zone” to prevent a foreign object, or a person, to be in closeproximity to the device 1400 where the E-Field or SAR value exceeds therequired limit. In some embodiments, the transmitter will be disabledwhen the one or more sensors detect the foreign object is within the“keep out zone”.

FIG. 18 is a flow diagram showing a method of wirelessly-transmittingenergy to a receiver device without using active beam-forming control inaccordance with some embodiments. Operations (e.g., steps) of the method1800 may be performed by a controller 309 (e.g., a controller 170 of theRFIC 160 of transmitter device 100 as shown in FIGS. 1A-1C, and/or apower amplifier controller IC 161A as shown in FIGS. 1B-1C), thetransmitter including one or more transmitter coverage areas (e.g.,transmitter coverage areas 290-1, FIGS. 1B-1C; which each includerespective one or more transmitters 300, FIG. 3 ). At least some of theoperations shown in FIG. 18 correspond to instructions stored in acomputer memory or computer-readable storage medium (e.g., memory 172and 174 of the transmitter device 100, FIG. 1B; memory 206 of the RFpower transmitter device 100).

The method 1800 includes providing (1802) a wireless-power transmitterdevice 100 (e.g., transmitter 300, FIG. 3 ) including at least oneantenna (e.g., antenna element 302, FIG. 3 ), one or more feed elements(e.g., feeds 304-A-304-N, FIG. 3 ), and a power amplifier (e.g., poweramplifier 306, FIG. 3 ) connected to the one or more feed elements. Insome embodiments, each antenna includes one or more feed elements. Insome embodiments, each antenna may include (i) a ground (e.g., groundplane 1510, FIGS. 15A-15C), (ii) a conductive wire (e.g., antennaelement 302, FIG. 3 ; loop antenna 1504, FIGS. 15A-15C) offset from theground, the conductive wire forming a loop antenna and/or any otherantenna type described above in FIG. 3 , (iii) one or more feed elements(e.g., feeds 304-A-304-N, FIG. 3 ) extending from the ground to theconductive wire, each feed element being connected to the conductivewire at a different position on the conductive wire (e.g., positionsA-N, FIG. 3 ), and (iv) a power amplifier (e.g., power amplifier 306,FIG. 3 ) connected to one or more feed elements of the one or more feedelements. In some embodiments, only one power amplifier controls andfeeds the power to the at least one antenna. In some embodiments, theoutput power provided by the single power amplifier is from 2 W to 15 W.In some embodiments, multiple power amplifiers are used to power one ormore antennas. In some embodiments, the power amplifier is a Class Epower amplifier. Alternatively or additionally, in some embodiments, thepower amplifier is a GaN (Gallium Nitride) power amplifier. In someembodiments, the ground (e.g., ground plane 1510, FIG. 15 ) includes aplurality of openings (not shown), and each of the one or more feeds isdisposed in a respective opening of the plurality of openings.Structural aspects of the wireless-power transmitter device 100 arediscussed in further detail above with reference to FIGS. 15A-15C.

In some embodiments, the method 1800 further includes selecting (1804),by a controller (e.g., controller 309 or a component thereof, such asone or more processors 318, FIG. 3 ) of the wireless-power transmitterdevice 100, a respective feed element of the one or more feed elementsbased on data received from one or more sensors (e.g., sensors 212). Insome embodiments, a location of a receiver device relative to the one ormore feed elements can be determined based on the data from the one ormore sensors and impedance measurements as disclosed herein (e.g., FIGS.4A-13 ). In some embodiments, the wireless-power transmitter device 100and a receiver use BLE communications paths to enable the wireless-powertransmitter device 100 to monitor and track the location of thereceiver. In some embodiments, the controller is coupled to the poweramplifier. For example, with reference to FIG. 3 , if the receiverdevice is located nearest feed element 304-A relative to the other feedelements 304-B-304-N, then the controller selects the feed element304-A. In some circumstances, the receiver device is located between twoor more of the feed elements. In such circumstances, the method 1800 mayinclude selecting, by the controller, at least two feed elements basedon a location of the receiver device relative to the one or more feedelements (determined based on the data from the one or more sensors andimpedance measurements as disclosed herein). Further, the controller mayselect all of the one or more feed elements in some instances.

In some embodiments, the method 1800 further includes sending (1806), bythe controller (e.g., controller 309), an instruction to the poweramplifier that causes the power amplifier to feed the RF signal to therespective feed element. For example, with reference to FIG. 3 , if therespective feed element is feed 304-A, then the controller 309 sends aninstruction (e.g., via busing 316) that causes the power amplifier toclose the switch 308-A, and in turn feed the RF signal to the feed304-A. In some embodiments, the one or more antennas are configured toradiate the RF signals with different propagation patterns depending onwhich of the one or more feed elements is fed by the single poweramplifier.

In some embodiments, the wireless-power transmitter device 100 includesa communications radio (e.g., communications component 204, FIG. 1A),and the method 1800 further includes receiving a communications signalfrom a corresponding communications radio of the receiver device.Further, the controller (or a component thereof) may determine thelocation of the receiver device relative to the one or more feedelements based on the communications signal (e.g., using informationincluded with or indicated by the communications signal). In someembodiments, the receiving and the determining are performed prior tothe selecting (1804) and the sending (1806). In some embodiments, thecontroller determines the location of the receiver device relative tothe one or more feed elements based on signal strength of thecommunication signal, triangulation, and/or response time (e.g., thereceiver device timestamps the communication signal when sent which isthen compared against a timestamp of the communication signal when it isreceived at the wireless-power transmitter device 100). Additionallocation determining techniques can also be used.

In some embodiments, the wireless-power transmitter device 100 includesone or more sensors (e.g., transmitter sensors 212, FIG. 2A), and themethod 1800 further includes detecting, via the one or more sensors, apresence of the receiver device. In some optional embodiments, thecontroller (or a component thereof) may determine the location of thereceiver device relative to the one or more feed elements based oninformation generated by the one or more sensors. In some embodiments,the detecting and the determining are performed prior to the selecting(1804) and the sending (1806). In some embodiments, the one or moresensors include one or more of a pressure sensor, an infrared sensor, anelectromagnetic sensor, an acoustic sensor, a capacitive sensor, a lightsensor, an inductive sensor, and a hall sensor. As an example, a lightsensor may detect a change in light near the wireless-power transmitterdevice 100 when the receiver device is positioned on or proximate to thewireless-power transmitter device 100. In some embodiments, a capacitivesensor detects a nearby object by the object's effect on the electricalfield of the capacitive sensor. In another example (in addition to orseparated from the previous example), an infrared sensor may detect achange in temperature near the wireless-power transmitter device 100when the receiver device is positioned on or proximate to thewireless-power transmitter device 100. In some embodiments, informationcollected from multiple sensors can be used to determine the location ofthe receiver device.

In some embodiments, each of the one or more feeds is associated with arespective sensor (e.g., the respective sensor is positioned near (orperhaps on) the feed and the respective sensor takes readings near thefeed). In this way, readings from each of the sensors can be compared(e.g., by the one or more processors 318), and the controller maydetermine the location of the receiver device relative to the one ormore feed elements based on the comparing. For example, if a largestchange in light occurs at feed 304-A relative to changes in lightoccurring at the other feeds, then the controller can determine that thereceiver device is located closest to the feed 304-A.

In some embodiments, the controller determines the location of thereceiver device relative to the one or more feed elements using two ormore forms of information (e.g., signal strength in combination with athermal imaging data, or some other combination communications-based andsensor-based information).

The method 1800 further includes selectively feeding (1808), by thepower amplifier, an RF signal to the respective feed element of the oneor more feed elements based on the data from the one or more sensors.For example, with reference to FIG. 3 , a first feed element 304-A ofthe one or more feed elements 302-A-302-N is connected to the conductivewire 302 at a first position and a second feed element 302-B, distinctfrom the first feed element 302-A, of the one or more feed elements302-A-302-N is connected to the conductive wire 302 at a secondposition. In such a configuration, the power amplifier: (i) may feed theRF signal to the first feed element when the location of the receiverdevice is within a threshold distance from the first position, and (ii)may feed the RF signal to the second feed element when the location ofthe receiver device is within the threshold distance from the secondposition. In some embodiments, feeding the RF signal to the one or morefeed elements includes feeding the RF signal to two of the one or morefeed elements upon determining that the location of the receiver deviceis between the two feed elements.

In some embodiments, the selective-feeding operation (1808) is performedin response to the power amplifier receiving the instruction from thecontroller.

In some embodiments, the method 1800 further includes (i) exciting, bythe respective feed element fed by the power amplifier, the conductivewire and then (ii) radiating, by the conductive wire, the RF signal forwirelessly powering the receiver device. The conductive wire may radiatethe RF signal from the conductive wire with different propagationpatterns depending on which of the one or more feed elements is fed bythe power amplifier. For example, the conductive wire radiates the RFsignal from the conductive wire in a first propagation pattern of thedifferent propagation patterns when a first feed element of the one ormore feed elements is fed by the power amplifier. In some instances, the“high concentration” of RF energy includes approximately 50 percent ofthe radiated energy, although greater and lesser percentages can beachieved. Also, a concentration of RF energy in the first propagationpattern forms around the first feed element and the first propagationpattern propagates away from the first feed element in a first direction(or a set of first directions) towards the location of the receiverdevice. In this way, the method 1800 allows for selectively activatingindividual feed elements of a loop antenna to ensure that RF energy ispropagated in such a way that a sufficiently high concentration of theRF energy is optimally propagated towards a location of a receiverdevice.

In another example, the conductive wire may radiate the RF signal in asecond propagation pattern of the different propagation patterns when asecond feed element of the one or more feed elements is fed by the poweramplifier. Also, a concentration of RF energy in the second propagationpattern forms around the second feed element and the second propagationpattern propagates away from the second feed element in a seconddirection (or a set of second directions) towards a location of thereceiver device.

In some embodiments, the method 1800 allows for selectively activatingindividual feed elements of a loop antenna to ensure that RF energy ispropagated in such a way that the RF energy below the predetermined SARthreshold is optimally propagated towards a location of a receiverdevice.

In some embodiments, the wireless-power transmitter device 100 isconfigured such that in use the first propagation pattern has a firstpolarization and the second propagation pattern has a secondpolarization. In some embodiments, the second polarization differs fromthe first polarization.

In some embodiments, the different propagation patterns are based, atleast in part, on a plurality of physical dimensions of thewireless-power transmitter device 100. The plurality of physicaldimensions may include but is not limited to: (i) a width of theconductive wire, (ii) a length of the conductive wire, (iii) a height ofthe conductive wire, (iv) a thickness of the conductive wire, (v) ashape of the loop, and (vi) a magnitude of the offset between the ground(e.g., ground plane 1510, FIG. 15 ) and the conductive wire. Physicalcharacteristics of the conductive wire (e.g., the antenna element 302)are discussed in further detail above with reference to FIGS. 3 and15A-15C.

In some embodiments, the conductive wire includes a plurality ofcontiguous segments (e.g., continuous segments of antenna elements302-A-302-N, FIG. 3 ), and each of the one or more feed elements ispositioned between a respective pair of adjacent segments of theplurality of contiguous segments (e.g., feeds 304-A-304-N positionedbetween segments 302-A-302-N). Further, in some embodiments, one or morefirst segments of the plurality of contiguous segments have a firstshape and one or more second segments of the plurality of contiguoussegments have a second shape different from the first shape. In someembodiments, each of the plurality of contiguous segments radiates theRF signal when one of the one or more feed elements is fed by the poweramplifier.

The method 1800 further includes determining (1810) whether there is aforeign object located in the respective power transmission field in azone where a determined SAR value is above a predetermined value. Insome embodiments, the SAR values within the power transmission field aremeasured with some external SAR value measurement equipment. In someembodiments, the resulting SAR values from the measurement are stored ina table in the memory of a controller of the wireless-power transmitterdevice 100. Based on the pre-determined existing SAR values within thepower transmission field, the sensor can determine if one or moreforeign objects (including a human being) is located or moves into alocation where the determined SAR value is above a predeterminedthreshold (the SAR keep out zone). In some embodiments, sensors are usedto detect if the foreign objects are in the SAR keep out zone and suchparametric measurements are done by sensors such as IR or capacitivesensors. In some embodiments, one or more sensors are associated with arespective power transmission field near a respective feed element. Insome embodiments, the sensors associated with the one or more feedsdetect electrical field strength or power transmission energy within theantenna radiation profile near the respective feed. The controllerreceives the foreign objects detection from the sensors.

The method 1800 further includes determining (1812) whether a foreignobject is located in the respective power transmission field in a zonewhere a determined SAR value is above a predetermined value. In someembodiments, the determined SAR values for a respective powertransmission field near the respective feed element will only be readinto the memory of a controller if there is a foreign object, such as ahuman being is at the same location within the same transmission field.If the foreign object is present in a zone where the SAR value for arespective power transmission field near the respective feed element isabove the predetermined value, the method 1800 includes a step ofadjusting (1814) feeding the power to the respective feed element orceasing transmission. In some embodiments, the adjusting feeding of thepower includes stop feeding the power to the respective feed element. Ifthe foreign object is present only in a zone where the SAR value for arespective power transmission field near the respective feed element isat or below the predetermined value or if the foreign object is notpresent in the respective power transmission field at all, the method1800 includes a step of continuing (1816) feeding the power to therespective feed element.

In some embodiments, if the controller determines that if the foreignobject is present in a zone where the SAR value for a respective powertransmission field near the respective feed element is above thepredetermined value, the controller sends instruction to the poweramplifier to adjust feeding the power to the respective feed element. Insome embodiments, if the foreign object is present in a zone where theSAR value for a respective power transmission field near the respectivefeed element is above the predetermined value, the controller sendsinstruction to the power amplifier to stop feeding the power to therespective feed element. In some embodiments, the predeterminedthreshold is the SAR limit under the US FCC requirement or the EU IECrequirement as described herein. In some embodiments, if the controllerdetermines that the foreign object is not present in a zone where theSAR value for a respective power transmission field near the respectivefeed element is above the predetermined value, the controller sendsinstruction to the power amplifier to continue feeding the power to therespective feed element.

In some embodiment, the wireless-power transmission system uses thesensors to manage the SAR keep out zone. For example, within a certaindistance to the antenna element, the electrical fields or SAR valuesmight exceed the US FCC or international requirements. In that case,when a sensor detects that a receiver or a foreign object is locatedwithin the prohibited SAR keep out zone where the electrical fields orSAR values exceed the limit, the method 1800 would invoke step 1814 asdescribed above. Different SAR regulatory standards are discussed below.

In some embodiments, a method of fabricating a wireless-powertransmitter device 100 (e.g., transmitter 300, FIG. 3 ; smart speaker1400, FIGS. 15A-15C) includes providing a ground (e.g., ground plane1510, FIGS. 15A-15C) and removing material from the ground to define oneor more openings (e.g., holes) in the ground. The one or more openingsbeing sized to receive feed elements (e.g., feeds 304-A-304-N). In someembodiments, the removing is performed using a drilling operation. Themethod further includes disposing/attaching a feed in each of the one ormore openings such that the wireless-power transmitter device 100includes one or more feeds. In some embodiments, each of the feeds ismechanically and/or chemically (e.g., using an adhesive) attached to itsrespective opening. The one or more feeds are substantiallyperpendicular to the ground and extend away from the ground. The methodfurther includes attaching an antenna element (e.g., antenna element302, FIG. 3 ; loop antenna 1504, FIGS. 15A-15C) to the one or morefeeds. In some embodiments, the antenna element is mechanically and/orchemically attached to the feeds. Connection points between the antennaelement and feed elements are discussed in further detail above withreference to FIG. 3 and FIGS. 15A-15C. The antenna element may be offsetfrom the ground by a distance. In some embodiments, the antenna elementis substantially parallel to the ground.

In some embodiments, one or more wireless-power transmitters 100 arefabricated using the method above, and grouped together to form atransmission system (i.e., an array of wireless-power transmitters 100).In some embodiments, the ground may be a single ground plane used by theone or more wireless-power transmitters 100. Alternatively, in someembodiments, each of the one or more wireless-power transmitters 100 hasa distinct ground. An array of wireless-power transmitters 100 may beformed by positioning each of the wireless-power transmitters 100 withinrespective transmitter coverage areas, and then interconnectingcomponents of each of the transmitter coverage areas with a commoncontroller for the transmitter.

FIG. 19 is a flow diagram 1900 showing a method of detecting a foreignobject using the measurements points connected to a power amplifier, inaccordance with some embodiments. Operations (e.g., steps) of the method1900 may be performed by a wireless power transmitting system (e.g. RFcharging pad 100, FIGS. 1A-1B, and 2A; charging pad 294, FIG. 1C;wireless power transmitter 400, FIG. 4 ) and/or by one or morecomponents thereof (e.g. an impedance measurement system 500, FIG. 5 ;the PAIC 161A, FIGS. 1B-1C, 3, 5-6 ). At least some of the operationsshown in FIG. 19 correspond to instructions stored in a computer memoryor computer-readable storage medium (e.g., memory 206 of the transmitterdevice 100, FIG. 2A).

The method 1900 includes a step 1902 of providing a power amplifier(e.g., power amplifier 402, FIG. 4 ).

The method 1900 also includes a step 1904 of providing a plurality ofmeasurement points connected to the power amplifier, the plurality ofmeasurement points configured to measure at least impedance (e.g., seevarious measurement points in FIGS. 4-6 ). In some embodiments,measurement points include the voltage at the output of the amplifier404, voltages at points inside the matching network 406 and 416, thevoltage at the drain of the transistors 408. In some embodiments, the DCcurrent and voltage consumed by each stage of the amplifier, such as theDC current measurement 410, voltage measurement 412, and the thermistorsfor temperature measurement at different stages of the amplifier, suchas 414.

The method 1900 further includes a step 1906 of providing a PAIC 161A(e.g., FIGS. 1B-1C, 3, and 5-6 ). In some embodiments, the PAIC 161A cansynchronize the turn on of all the modules of the power amplifier, forexample, the power amplifier bias circuits, and the power amplifierpower supply network. In some embodiments, the PAIC 161A can perform allof the required analog measurements. In some embodiments, the PAIC 161Acan adjust the output power and bias conditions of the power amplifierto maintain optimum efficiency and output power. In some embodiments,the PAIC 161A can synchronize the shut-down of various components of thepower amplifier.

The method 1900 further includes a step 1908 of performing at leastimpedance measurements at the plurality of measurement points usingmeasurement values (e.g., as described in FIG. 4 ) from the plurality ofmeasurement points and data from one or more sensors (e.g., sensors212). In some embodiments, the measurements are performed by the RFIC160 and/or PAIC 161A. In some embodiments, the measurements alsoincluding temperature measurements by thermistors integrated with apower amplifier.

The method 1900 further includes a step 1910 of detecting a foreignobject in proximity to or within a transmission range of thetransmitter. In some embodiments, the PAIC 161A can determine if themeasurement results (based on LUTs stored in memory 206, and/or usingdata from one or more sensors and impedance measurements to referencethe LUTs) could damage the power amplifier and if so quickly shutdownthe power amplifier. For example, as described in FIGS. 9 , the PAIC161A can use the measurement results to determine whether the impedancethresholds are satisfied. As another example, as described in FIGS.10-13 , the PAIC 161A can use the measurement results to determinewhether the power amplifier is operating within the VSWR thresholdsand/or dissipation power thresholds, and/or if power scaling needs to beperformed. In some embodiments, the PAIC 161A can use the measurementresults to determine whether to shut-down the PA. In some embodiments,the PAIC 161A determines if there is a foreign object or a validreceiver while the transmitter is charging (using the data from one ormore sensors and/or the impedance measurements as described herein). Aforeign object can be determined in the case of a discontinuity inimpedance. For example, if a foreign object is detected, an impedancemeasurement will not be on any of the contours described above inreference to the Smith charts (e.g. FIGS. 7-13 ), or may be located at aposition that does not have an intersection or multiple intersections.

FIGS. 20A-20D are flow diagrams showing a method ofwirelessly-transmitting energy to a receiver device without using activebeam-forming control in accordance with some embodiments. The methodsdescribed below allow for the efficient and effective transmission ofwireless power signals by controlling and managing the power amplifierwhile forgoing any modifications to the amplified RF signal (e.g., thesystem does not modify phase, gain, etc. such that no active beamformingoccurs). The methods describe below also allow for the determinationthat one or more safety thresholds (e.g., user-safety thresholds and/orpower-amplifier-protection thresholds) are satisfied by an RF signal asdisclosed above. Further, the methods described below can be performedwithout tuning the one or more antennas. In some embodiments, antennatuning can be combined with the methods described below (e.g., themethods described below can be performed independent of antenna tuning).Operations (e.g., steps) of the method 2100 may be performed by one ormore integrated circuits (e.g., RFIC 160 of transmitter device 100 asshown in in at least FIGS. 1A-1C, and/or a PAIC 161A as shown in atleast FIGS. 1B-1C), the transmitter including one or more transmittercoverage areas (e.g., transmitter coverage areas 290-1, FIGS. 1B-1C;which each include respective one or more transmitters (e.g. TX Antennas210, FIGS. 1A-1C)). At least some of the operations shown in FIGS.20A-20D correspond to instructions stored in a computer memory orcomputer-readable storage medium (e.g., memory 172 and 174 of thetransmitter device 100, FIG. 1B; memory 206 of the RF power transmitterdevice 100).

The method 2000 receiving (2002) an indication that a wireless-powerreceiver is located within one meter of the wireless-power transmissionsystem and is authorized to receive wirelessly-delivered power from thewireless-power transmission system. In some embodiments, the indicationthat the wireless-power receiver is located within one meter of thewireless-power transmission system is received via data from one or moresensors (e.g., 212). In some embodiments, the indication that thewireless-power receiver is located within one meter of thewireless-power transmission system is received via a BLE signal and/orother communication protocol sent by the wireless-power receiver.Similarly, in some embodiments, the wireless-power receiver isdetermined to be authorized to receive wirelessly-delivered power fromthe wireless-power transmission system based on the data from one ormore sensors, BLE signal, and/or other communication protocol sent bythe wireless-power receiver. Alternatively or additionally, in someembodiments, the indication that the wireless-power receiver is locatedwithin one meter of the wireless-power transmission system is receivedby detecting a change in impedance at the power amplifier (as discussedabove). Similarly, in some embodiments, the wireless-power receiver isdetermined to be authorized to receive wirelessly-delivered power fromthe wireless-power transmission system based on detecting change inimpedance and utilizing one or more signature-signals as discussedherein.

Method 2000 includes, in response to receiving the indication, selecting(2004) a power level from among a plurality of available power levels atwhich to amplify a radio frequency (RF) signal using a power amplifier.In some embodiments, the power level selected based on one or morelookup tables (LUT)s. In some embodiments, the LUTs include measurementvalues obtained during simulation, characterization, and/ormanufacturing tests of the wireless-power transmitter device 100. Insome embodiments, the indication includes information that allows thewireless-power transmission system to determine a location of thewireless-power receiver, and the power level among the plurality ofavailable power levels is selected based, at least in part, on thelocation of the wireless-power receiver. Alternatively, rather thanbasing selection of the power level on the receiver's location, in someother embodiments, the wireless-power transmitter device 100 selects amaximum power level among the plurality of available power levels, themaximum power level being the highest power level (e.g. 15 W) of theplurality of available power levels that satisfies one or more safetythresholds as described below. For example, the wireless-powertransmitter device 100 can select a first power level (e.g., the maximumpower level) at a first time and, based on a determination that thefirst power level fails to satisfy the one or more safety thresholds,select a second power level (e.g., the second power level being lessthan the maximum power level).

In some embodiments, the selected (2006) power level is a maximum powerlevel from among the plurality of available power levels. In someembodiments, the power level is selected (2008) from among the pluralityof available power levels of the power amplifier when the wireless-powerreceiver is at most 40 cm from the wireless-power transmitter device100. In some embodiments, the power level is selected (2010) from amongthe plurality of available power levels of the power amplifier when thewireless-power receiver is within 20 cm to 40 cm from the wireless-powertransmitter device 100. In some embodiments, the power level (2012) isbetween 2 watts and 15 watts. In some embodiments, the selected powerlevel at which to generate the RF signal is increased as the distancebetween the wireless-power receiver between and the wireless-powertransmitter device 100 increases.

The method 2000 includes, in accordance with a determination thattransmitting the RF signal to the wireless-power receiver would satisfy(2014) one or more safety thresholds, instructing (2014-a) the poweramplifier to amplify the RF signal using the power level to create anamplified RF signal, and providing (2014-b) the amplified RF signal toone or more antennas. The one or more antennas are caused to, uponreceiving the amplified RF signal, radiate RF energy that is focusedwithin an operating area that includes the wireless-power receiver whileforgoing any active beamforming control. In some embodiments, radiatedRF energy is said to be focused within an operating area that includesthe wireless-power receiver when a peak level of RF energy is at itsmaximum at the location of the wireless-power receiver. In someembodiments, the method 2000 instructs (2014-a) the power amplifier toamplify the RF signal using the power level while forgoing anymodification to the amplified RF signal that is consistent withbeamforming. In other words, the wireless-power transmitter device 100does not modify the phase, gain, etc. of an RF signal for beamformingpurposes. In some embodiments, the method 2000 includes, in accordancewith a determination that no power level from among the plurality ofavailable power levels that would satisfy the one or more safetythresholds, instructing the power amplifier to shut down. As discussedherein, a determination that a power level from among the plurality ofavailable power levels would satisfy the one or more safety thresholdsis based data retrieved from one or more LUTs.

By determining that transmitting the RF signal to the wireless-powerreceiver would satisfy (2014) one or more safety thresholds beforeinstructing (2014-a) the power amplifier ensures that an appropriatepower level (e.g., safe and efficient) from among the plurality ofavailable power levels is selected for use in amplifying the RF signal,such that the one or more safety thresholds will still be satisfiedafter the RF signal is transmitted. In particular, the system canreference stored values in LUTs to select a power level that is known tosatisfy the one or more safety thresholds. Alternatively oradditionally, in some embodiments, the system can predict thattransmitting the RF signal in the future would result in a formation ofRF energy at the wireless-power receiver that satisfies the one or moresafety thresholds, the prediction based on referencing, at least, thedynamically obtained impedance measurements with the LUTs (data from oneor more sensors can also be used to reference the LUTs). Non-exhaustiveexamples of the safety thresholds are discussed in detail below and inFIG. 5 .

In some embodiments, the one or more safety thresholds include (2016) amaximum specific absorption rate (SAR) value of not greater than 2 W/kg,and the determination that transmitting the RF signal would satisfy theone or more safety thresholds is made when it is determined thattransmitting the RF signal would create a maximum SAR value of notgreater than 2 W/kg at the wireless-power receiver (e.g., determined byreferencing one or more LUTs, or by ensuring that the system uses onlythose operation characteristics (e.g., operational impedance, outputpower, etc.) designed to ensure that the SAR value is always satisfied).In some embodiments, the one or more safety thresholds include (2018) amaximum specific absorption rate (SAR) value of not greater than 0.8W/kg, and the determination that transmitting the RF signal wouldsatisfy the one or more safety thresholds is made when it is determinedthat transmitting the RF signal would create a maximum SAR value of notgreater than 0.8 W/kg at the wireless-power receiver (e.g., determinedby referencing one or more LUTs or by ensuring that the system uses onlythose operation characteristics (e.g., operational impedance, outputpower, etc.) designed to ensure that the SAR value is always satisfied).In some embodiments, the wireless-power transmitter device 100 describedherein is capable of even greater control over the maximum SAR value,such as by ensuring that radiated RF energy focused within an operatingarea that includes the wireless-power receiver will create a maximum SARvalue that is no greater than a value of 1.6 W/kg, 1.5 W/kg, 0.7 W/kg,down to a value as low as 0.5 W/kg.

In some embodiments, the one or more safety thresholds include (2020) apredetermined roll-off of 3 dB at each predetermined distance incrementrelative to a peak amount of RF energy produced by radiated RF energy,and the determination that transmitting the RF signal would satisfy theone or more safety thresholds is made when it is determined thattransmitting the RF signal would create a peak amount of RF energy atthe wireless-power receiver that has the predetermined roll-off of 3 dBfor each predetermined distance increment relative to the peak amount ofRF energy (e.g., determined by referencing one or more LUTs or byensuring that the system uses only those operation characteristics(e.g., operational impedance, output power, etc.) designed to ensurethat the e-field roll-off value is always satisfied). In someembodiments, the predetermined distance increment (2022) is about 8 cm.In some embodiments, “about 8 cm” refers to +/−0.5 cm of 8 cm, so therange would be between 7.5-8.5 cm. For example, as shown in FIG. 17 , insome embodiments, the RF energy can be focused within an operating areathat includes a location of a receiver 104. The RF energy at thelocation of the receiver 104 is at its peak 1702 (or maximum for theselected power level) and rolls off 1706 by a predetermined roll-off of3 dB for each predetermined distance increment 1704. As another example,as shown in FIG. 18 , in some other embodiments, the RF energy isfocused directly in front of the wireless-power transmitter device 100with its peak RF energy at the center point 1006. The RF energy focusedwithin an operating area that includes the center point 1006 rolls offby a predetermined roll-off of 3 dB for each predetermined distanceincrement (additional example and explanation provided in FIG. 16 ).

In some embodiments, the method 2000 includes modeling the peak amountof RF energy that would be produced at the wireless-power receiver for aselected power level, and then determine whether the predeterminedroll-off of 3 dB is going to be satisfied (e.g., for at least onepredetermined distance increment). While the primary example given herefor illustrative purposes is a predetermined 3 dB roll-off value, insome embodiments, other suitable predetermined roll-off values can beutilized. For example, as described above in FIGS. 17 and 18 , in someembodiments, the predetermined roll off can be less than 3 dB (e.g., 1dB) for distances below the predetermined distance increment.Alternatively or additionally, in some embodiments, the predeterminedroll off can be greater than 3 dB (e.g., 4 to 5 dB) for distancesgreater than the predetermined distance increment. Similarly, othersuitable predetermined distance increment values can be used (asdescribed above in FIGS. 16 and 17 ). For example, in some embodiments,the predetermined distance increment is based on the wavelength (k) ofthe emitted electromagnetic waves.

In some embodiments, the wireless-power transmitter device 100 includes(2024) only a single power amplifier and the one or more antennasinclude only a single antenna. Designing a wireless-power transmitterdevice 100 that is capable of complying with the one or more safetythresholds using only a single PA and only a single antenna results in alow-cost system that is still able to achieve a safe transmission ofwireless power, thus producing a system that is commercially viable bothfor its ability to comply with regulatory requirements and for itsability to be built at a cost point that is palatable for customers.Such a wireless-power transmitter device 100 also places a lowercomputing requirements on the one or more ICs, because less componentsneed to be controlled, and also because the system does not require anyactive beamforming control.

In some embodiments, the method 2000 includes determining (2026-a) anoperational impedance at the power amplifier based on an impedancemeasurement from among multiple measurement points of the poweramplifier, and the one or more safety thresholds include (2026-b) one ormore impedance thresholds indicating that the operational impedance isat a safe level, and the determination that transmitting the RF signalwill satisfy the one or more safety thresholds is made when it ispredicted that using the power level to amplify the RF signal would keepthe operational impedance at the power amplifier at or below the one ormore impedance thresholds. The operational impedance of the poweramplifier can be determined at various different measurements using adifferent combination of parametric parameters of the device (asdescribed above in FIGS. 7-13 )

In some embodiments, the method 2000 includes receiving (2028-a) animpedance measurement from among the multiple measurement points of thepower amplifier. The method 2000 includes utilizing (2028-b) theimpedance measurement to retrieve information for stored measurementvalues for two or more parametric parameters, the stored measurementvalues for the two or more parametric parameters indicating that theoperational impedance is a safe operational impedance for the poweramplifier. Visual representations of the stored measurements for the twoor more parametric parameters defining the safe operational impedance ofthe power amplifier are shown by the predetermined intersections on theSmith chart (e.g., FIG. 9 ). The method 2000 further includes selecting(2028-c) the power level upon determining that the operational impedanceis a safe operational impedance for the power amplifier. Determiningthat the impedance measurement corresponds to the stored measurementvalues for two or more parametric parameters in the LUT, in someembodiments, means that the impedance measurement is known or can beapproximated (e.g., extrapolated value from the operating impedances) asthe safe operational impedance for the power amplifier. For example, asvisually represented in FIGS. 7-9 , stored measurement values for two ormore parametric parameters map to respective predetermined intersectionon the Smith chart that can be used to determine or predict theoperational impedance. As described above in FIGS. 7 and 8 , the storedmeasurement values for two or more parametric parameters (represented aspredetermined contours of two or more parametric parameters) can beobtained during simulation, characterization, and/or manufacture testsof the wireless-power transmitter device 100. A non-exhaustive list ofthe parametric parameters include Vdrain power, DC Power, Vout_contour,and/or power dissipation. Additional examples and explanations of theparametric parameters and their use with the Smith charts are providedabove in FIGS. 7-13 . Additionally or alternatively, data from one ormore sensors can be used in conjunction with the impedance measurementsto determine (by using the LUTs) a safe operational impedance for thepower amplifier.

In some embodiments, the method 2000 includes receiving (2030-a) animpedance measurement from among multiple measurement points of thepower amplifier. The method 2000 includes utilizing (2030-b) theimpedance measurement to retrieve information for stored measurementvalues for two or more parametric parameters (e.g., Vout and powerdissipation as described above), the stored measurement values for thetwo or more parametric parameters indicating that the operationalimpedance is a safe operational impedance for the power amplifier.Visual representations of the stored measurements for the two or moreparametric parameters defining a safe operational impedance of the poweramplifier are shown by the predetermined intersections on the Smithchart (e.g., FIGS. 8 and 12-13 ) The method 2000 further includesdetermining (2030-c) a dissipation level corresponding to the retrievedinformation, and decreasing (2030-d) the power level upon determiningthat the dissipation level at the impedance measurement is above adissipation threshold. Examples of using the dissipation threshold isprovided above in FIGS. 12-13 . Additionally or alternatively, data fromone or more sensors can be used in conjunction with the impedancemeasurements to determine (by using the LUTs) a dissipation level at theimpedance measurement.

In some embodiments, the power level is dynamically determined (2032)using the one or more LUTs while the RF energy is focused within anoperating area that includes the wireless-power receiver without anyactive beamforming control. As described above, the power level can beadjusted (e.g., dynamically determined) based on changes to the detectedimpedances, a receiver and/or foreign object entering or leaving atransmission field, movement of a receiver and/or foreign object, and/orother situations as described above. The dynamic adjustments are basedon the simulation, characterization, and/or manufacture tests of thewireless-power transmitter device 100 and/or one or more antennas of thetransmitter device 100.

In some embodiments, the method 2000 includes receiving (2034-a), fromone or more sensors, a shut-off indication that indicates that an object(e.g., a foreign object or a person) is within a predefined shut-offdistance of the wireless-power transmitter device 100. The method 2000,in response to receiving the shut-off indication, causes (2034-b) theone or more antennas to cease radiating the RF energy. In someembodiments, the predefined shut-off distance is (2036) approximately 20cm from the wireless-power transmitter device 100. In some embodiments,the 20 cm is measured radially from a center point of the system, suchas is depicted by the 20 cm long radial arrows illustrated in FIG. 14D.In some embodiments, the one or more sensors of the wireless-powertransmitter device 100 are IR sensors. In some embodiments approximately20 cm references to +/−1 cm off of 20, so a range of 19 to 21 cm.

In some embodiments, receiving the indication that the wireless-powerreceiver is located within one meter of the wireless-power transmitterdevice 100 and is authorized to receive wireless charging from thewireless-power transmitter device 100, and selecting the power level atwhich to generate the RF signal are performed (2038-a) at a firstintegrated circuit. The first IC is, for example, the RFIC 160. In someembodiments, the indication that the wireless-power receiver is locatedwithin one meter of the wireless-power transmitter device 100 and isauthorized to receive wireless charging from the wireless-powertransmitter device 100 is received from one or more sensors (e.g.sensors 212) of the wireless-power transmitter device 100. In someembodiments, controlling and managing one or more operations of thepower amplifier including instructing the power amplifier to amplify theRF signal are performed (2038-b) at a second integrated circuit. Thesecond IC is, for example, the PAIC 161A. As described above, the firstIC and the second IC are communicatively coupled to each other and areconfigured to work with each other in performing the operationsdescribed above. In some embodiments, the first IC and the second ICprovide instructions to each other. In some embodiments, having twodifferent integrated circuits is beneficial because it makes it easierto control the distribution of heat, distribute the processing betweenthe ICs. In some embodiments, having two different integrated circuitsenables older wireless-power transmitters to be retrofitted.Alternatively or additionally, in some embodiments, it more efficient,for cost purposes, to design and use two different ICs

In some embodiments, determining an operational impedance at the poweramplifier may be performed (2040) at the second IC (e.g., to reduce theprocessing on the first IC). In some embodiments, the second IC may alsostore the Smith charts and/or one or more contours to be loaded on theSmith Chart for performing operations of the method described above.

In some embodiments, the method 2000 includes receiving (2042-a)charging information from the wireless-power receiver. The method 2000includes selecting (2042-b) the power level from among the plurality ofavailable power levels based, at least in part, on the charginginformation from the wireless-power receiver. In some embodiments, thecharging information includes a request for power, the requestspecifying power limits, SAR limits, and/or other parameters specific tothe wireless-power receiver. In some embodiments, the charginginformation is received via a communication radio. In some embodiments,the communication radio operates using the Bluetooth Low Energy (BLE)protocol and/or other protocols described above. In some embodiments,the charging information is received in a packet of information that isreceived in conjunction with the indication that the wireless-powerreceiver is located within one meter of the wireless-power transmitterdevice 100 and is authorized to receive wirelessly-delivered power fromthe wireless-power transmitter device 100. In other words, thewireless-power receiver can use a wireless communication protocol (suchas BLE) to transmit the charging information as well as authenticationinformation to the one or more integrated circuits).

In some embodiments, the one or more safety thresholds can be satisfiedbased on the charging information received from the wireless-powerreceiver. For example, the charging information can includes a SAR valuemeasured at the wireless-power receiver, an effective power measured atthe receiver (e.g., transmitted power converted into usable power), ameasured impedance, and/or any other information to make a determinationon the one or more safety thresholds described herein.

In some embodiments, the wireless-power receiver is configured to chargea coupled electronic device (e.g., a mobile phone, a watch, a hearingaid, and/or other smart devices).

FIGS. 21A-21C are flow diagrams showing a method of controlling and/ormanaging operation of one or more power amplifiers in accordance withsome embodiments. Operations (e.g., steps) of the method 2100 may beperformed by one or more integrated circuits (e.g., RFIC 160 oftransmitter device 100 as shown in in at least FIGS. 1A-1C, and/or aPAIC 161A as shown in at least FIGS. 1B-1C, 3, 5-6 ), the transmitterdevice 100 including one or more power amplifiers. At least some of theoperations shown in FIGS. 21A-21C correspond to instructions stored in acomputer memory or computer-readable storage medium (e.g., memory 172and 174 of the transmitter device 100, FIG. 1B; memory 206 of the RFpower transmitter device 100).

Method 2100 includes receiving (2102) impedance measurements at aplurality of measurement points of the power amplifier and data from oneor more sensors. The plurality of measurement points allow measurementsof at least an impedance measurement at each respective measurementpoint. In some embodiments, the impedance measurements at the pluralityof measurement points include (2104) one or more of: voltage at anoutput of the power amplifier, voltages at points inside a matchingnetwork, voltage at a drain of a transistors of the power amplifier, aDC current and voltage consumed by each stage of the power amplifier,and thermistors at different stages of the power amplifier. Thedifferent measurement points are described above in FIG. 4 . In someembodiments, the plurality of measurement points are (2106) measured atmultiple output power levels of the power amplifier (e.g., as describedabove in FIGS. 4, 7, and 8 ). Additionally or alternatively, in someembodiments, method 2100 includes receiving data from one or moresensors of the wireless-power transmitter device 100. The data from oneor more sensors (e.g. sensors 212) of the wireless-power transmitterdevice 100 can be used in conjunction with the received impedancemeasurements at the plurality of measurement points of the poweramplifier.

In some embodiments, the power amplifier includes (2108) a thermistorthat measures temperature. In some embodiments, the thermistor is on(2110) a same chip as other components of the power amplifier.

Method 2100 includes detecting (2112) presence of a foreign objectwithin 6 inches of the wireless-power transmitter device 100 based onthe received impedance measurements and the data from one or moresensors, and adjusting radiated radio frequency (RF) energy that isfocused within an operating area that includes a wireless-power receiverwhile the presence of the foreign object is detected.

Method 2100 includes detecting (2114) absence of the foreign objectwithin the 6 inches of the wireless-power transmitter device 100 basedon the received impedance measurements and the data from one or moresensors (or lack thereof), and causing the radiation of the RF energyfocused within an operating area that includes the wireless-powerreceiver upon determining that the foreign object is absent.

In some embodiments, method 2100 includes using (2116) the plurality ofmeasurement points and/or the data from the one or more sensors with oneor more lookup tables (LUT)s to measure an operational impedance at thepower amplifier. In some embodiments, method 2100 includes determining(2118) a power level at which to generate the radio frequency (RF)signal that satisfies on one or more power amplifier operation criteriathat protect the power amplifier from damage, and a determination thatthe power level would satisfy the one or more power amplifier operationcriteria is based, at least in part, on the operational impedance at thepower amplifier. In some embodiments, method 2100 includes instructing(2120) the power amplifier to shut down if the one or more poweramplifier operation criteria is not satisfied. In some embodiments, theone or more power amplifier operation criteria include the one or moreimpedance thresholds as described above in FIGS. 7-13 .

In some embodiments, method 2100 includes storing (2122) one or moremeasurements values from the plurality of measurement points and/or datafrom the one or more sensors for subsequent analysis. In particular, theone or more measurements values from the plurality of measurement pointscan be stored into the one or more LUTs (e.g., updating and/or buildingon the LUTS) and used to improve the accuracy of future impedancedeterminations. In some embodiments, the stored measurement can be usedto improve the overall speed of the impedance determinations (e.g., byallowing the system to avoid having to repeat calculations and/ordeterminations). Other uses of the stored measurement values arediscussed above in FIGS. 4, 7, and 8 .

In some embodiments, method 2100 includes synchronizing (2124) turn-onof power amplifier bias circuits, and turn-on of a power amplifier powersupply network. In some embodiments, the power amplifier includes (2126)a single digital input pin and configured to synchronize turn-on ofpower amplifier bias circuits, and turn-on of a power amplifier powersupply network via the single digital input pin. In some embodiments,method 2100 includes synchronizing (2128) shut-down of variouscomponents of the power amplifier. In some embodiments, the poweramplifier includes (2130) a single digital input pin and the one or moreintegrated circuits are configured to synchronize shut-down of variouscomponents of the power amplifier via the single digital input pin.

In some embodiments, method 2100 includes adjusting (2132) output powerand bias conditions of the power amplifier to maintain optimumefficiency and output power. In some embodiments, adjustment to thepower amplifier and/or other configurations of a wireless-powertransmission system are based on predetermined properties and/orcharacteristics of the wireless-power transmission system obtainedduring simulation, characterization, and/or manufacture tests of thewireless-power transmitter device and/or one or more antennas of thetransmitter device. In some embodiments, the power amplifier is (2134) aGaN (Gallium Nitride) power amplifier. Alternatively or additionally, insome embodiments, the power amplifier is (2136) a Class E amplifier.

FIG. 22 is flow diagram showing a method of controlling and/or managingoperation of one or more power amplifiers to optimize the performance ofthe one or more antennas in accordance with some embodiments. Operations(e.g., steps) of the method 2200 may be performed by one or moreintegrated circuits (e.g., RFIC 160 of transmitter device 100 as shownin in at least FIGS. 1A-1C, and/or a PAIC 161A as shown in at leastFIGS. 1B-1C, 3, 5-6 ), the transmitter including one or more poweramplifiers. At least some of the operations shown in FIG. 22 correspondto instructions stored in a computer memory or computer-readable storagemedium (e.g., memory 172 and 174 of the transmitter device 100, FIG. 1B;memory 206 of the RF power transmitter device 100).

Method 2200 is a method of operating an antenna, and includesdynamically adjusting (2202) power distribution for a transmission fieldof the antenna provided to a wireless-power receiver. Dynamicallyadjusting the power distribution for the transmission field includes, ata power amplifier controller integrated circuit (IC) (e.g., PAIC 161A),adjusting (2204) power provided to the antenna from a power amplifier.In some embodiments, the power provided to the antenna from the poweramplifier is adjusted (2206) based on the power amplifier controller ICdetecting a change in impedance. A change in impedance can be determinedbased on impedance measurements described above in FIGS. 4-13 . In someembodiment, the change in impedance can be determined based on datareceived from one or more sensors (e.g., 212). Alternatively oradditionally, the change in impedance can be determined based oncharging information received by a wireless-power receiver (via acommunication component). For example, in some embodiments, the change(2208) in impedance is movement of the wireless-power receiver.Dynamically adjustments to the power distribution of the antenna arebased on stored valued of the radiation profile and/or other componentsof the wireless-power transmitter device 100 that are obtained duringsimulation, characterization, and/or manufacture tests of thewireless-power transmitter device 100 and/or one or more antennas of thetransmitter device 100.

Method 2200 includes adjusting (2210) the power distribution for thetransmission field based on the adjusted power provided to the antennafrom the power amplifier such that: the adjusted power provided isevenly distributed (2212) across the power distribution for thetransmission field of the antenna; and a power loss at an edge of thepower distribution for the transmission field of the antenna is reduced(2214) from 30% to 10%. For example, as shown in FIG. 14E, a firsttransmission field (e.g., 1402) can be improved to a second transmissionfield (1418) through one or more changes to the PA (via the RFIC 160and/or PAIC 161A). In some embodiments, dynamically optimizing thetransmitted power signals is performed (2216) independent of (dynamic orstatic) tuning the antenna. In other words, method 2200 can be performedwithout moving and/or shifting the antennas or selectively activatingone or more antennas. In some embodiments, method 2200 can be performedin conjunction with antenna tuning (dynamic or static). The aboveexplained adjustments to the power distribution for a transmission fieldare and/or dynamic optimization of the transmitted power signals areperformed while forgoing beamforming.

FIG. 23 is an example flow diagram for transmitting RF energy from awireless-power transmitting device 100 in accordance with someembodiments. Operations (e.g., steps) of the method 2300 may beperformed by one or more integrated circuits (e.g., RFIC 160 oftransmitter device 100 as shown in in at least FIGS. 1A-1C, and/or aPAIC 161A as shown in at least FIGS. 1B-1C, 3, 5-6 ), the transmitterdevice 100 including one or more power amplifiers. At least some of theoperations shown in FIG. 23 correspond to instructions stored in acomputer memory or computer-readable storage medium (e.g., memory 172and 174 of the transmitter device 100, FIG. 1B; memory 206 of the RFpower transmitter device 100).

At operation 2302, the method 2300 includes receiving impedancemeasurements from around/inside a power amplifier (PA) operating at aselected output power. The selected power level is selected from among aplurality of available power levels at which to amplify a radiofrequency (RF) signal using a power amplifier of the wireless-powertransmitter device. In some embodiments, the impedance measurements canbe received from one or more measurement points as shown in FIG. 4 . Atoperation 2304, the method 2300 includes determining, by referencing alookup table (LUT) (stored in memory 206) using a CPU, an operationalimpedance for the PA (operating at the selected output power) based onone or more of the impedance measurements. For example, the CPU can usethe LUT to reference the impedance measurements to determine theoperational impedance of the PA. Alternatively or additionally, in someembodiments, the power level is selected from among a plurality ofavailable power levels based on the LUT. In some embodiments, data fromone or more sensors (e.g. 212) is used in conjunction with the impedancemeasurements to determine the operational impedance for the PA (e.g.,the data from the one or more sensors is used as an additionalmeasurement value to be referenced when performing lookups in the LUT).Visual representations of the above operations are provided anddescribed above in FIG. 9 . In particular, FIG. 9 shows that the one ormore impedance measurements can be used with one or more storedmeasurements for at least two parametric parameters (represented ascontours) to determine (or predict) an operational impedance for the PAoperating at the selected output power.

In some embodiments, the parametric parameters include the DC currentand voltage consumed by each stage of the amplifier, temperaturemeasurements, DC Power, voltage at the output of the amplifier, voltagedrain power and/or voltage at the drain of the transistors, powerdissipation, and/or voltages at points inside the matching networks.

At operation 2306, the method 2300 determines whether the operationalimpedance (determined at operation 2304) for the selected output powersatisfies one or more safety thresholds. The one or more safetythresholds are described above in reference to FIG. 5 . In someembodiments, the one or more safety thresholds are predetermined basedon simulation, characterization, and/or manufacturing tests of thewireless-power transmitter device 100 and/or one or more antennas of thetransmitter device 100. For example, SAR values and predetermined SARthresholds for different configurations, operational scenarios, powerlevels, etc. can be determined during simulation, characterization,and/or manufacturing tests of the wireless-power transmitter device. Inaccordance with a determination that the operational impedance(determined at operation 2304) for the selected output power satisfiesone or more safety thresholds (by referencing the LUT), the method 2300proceeds to operation 2308 and provides an RF signal amplified at theselected output power to one or more antennas that cause the one or moreantennas to transmit RF energy. In some embodiments, after providing theRF signal to the one or more antennas, the method 2300, returns tooperation 2302 to continuously monitor the impedance measurements forthe selected output power.

At operation 2306, in accordance with a determination that theoperational impedance (determined at operation 2304) for the selectedoutput power does not satisfy one or more safety thresholds, the method2300 proceeds to operation 2310 and determines, using the CPU toreference the LUT, a dissipation level for the operational impedance. Avisual representation of the determination of the dissipation level forthe operational impedance is described above in FIG. 12 . At operation2312, the method 2300 determines whether the dissipation level(determined at operation 2310) is above a dissipation threshold (byreferencing the LUT). In accordance with a determination that thedissipation level for the operational impedance is not above thedissipation threshold, the method 2300 proceeds to operation 2308 andprovides an RF signal amplified at the selected output power to the oneor more antennas to transmit RF energy (as described above).

At operation 2312, in accordance with a determination that thedissipation level for the operational impedance is above the dissipationthreshold, the method 2300 proceeds to operation 2314 and determines, byperforming power scaling, whether a new power level that has adissipation level below the dissipation threshold can be determined.Power scaling is described above in reference to FIG. 13 . In accordancewith a determination that a new power level that has a dissipation levelbelow the dissipation threshold cannot be determined (by referencing theLUT), the method 2300 proceeds to operation 2316 and does not transmitRF energy. In some embodiments, after determining not to transmit the RFenergy, the method 2300, returns to operation 2302 to continuouslymonitor the impedance measurements if another output power is selected.

At operation 2314, after determining a new power level that has adissipation level below the dissipation threshold (determined byreferencing the LUT), the method 2300 proceeds to operation 2318 andselects the new power level as the output power level. After selectingthe new power level as the output power level, the method 2300 proceedsto operation 2306 to determine whether the operational impedance for thenew power level satisfies the one or more safety thresholds. In thisway, the new power level is determined to be safe before thewireless-power transmitter uses the power level in conjunction withtransmission of RF energy.

Further embodiments also include various subsets of the aboveembodiments including embodiments in FIGS. 1-23 combined or otherwisere-arranged in various embodiments.

Safety Techniques

Any of the various systems and methods described herein can also beconfigured to utility a variety of additional safety techniques. Forinstance, a transmitter device can determine the present SAR value of RFenergy at one or more particular locations of the transmission fieldusing one or more sampling or measurement techniques. In someembodiments, the SAR values within the transmission field are measuredand pre-determined by SAR value measurement equipment. In someimplementations, a memory associated with the transmitter device may bepreloaded with values, tables, and/or algorithms that indicate for thetransmitter device which distance ranges in the transmission field arelikely to exceed to a pre-stored SAR threshold value. For example, alookup table may indicate that the SAR value for a volume of space (V)located some distance (D) from the transmitter receiving a number ofpower waves (P) having a particular frequency (F). One skilled in theart, upon reading the present disclosure, will appreciate that there areany number of potential calculations, which may use any number ofvariables, to determine the SAR value of RF energy at a particularlocations, each of which is within the scope of this disclosure.

Moreover, a transmitter device may apply the SAR values identified forparticular locations in various ways when generating, transmitting, oradjusting the radiation profile. A SAR value at or below 1.6 W/kg, is incompliance with the FCC (Federal Communications Commission) SARrequirement in the United States. A SAR value at or below 2 W/kg is incompliance with the IEC (International Electrotechnical Commission) SARrequirement in the European Union. In some embodiments, the SAR valuesmay be measured and used by the transmitter to maintain a constantenergy level throughout the transmission field, where the energy levelis both safely below a SAR threshold value but still contains enough RFenergy for the receivers to effectively convert into electrical powerthat is sufficient to power an associated device, and/or charge abattery. In some embodiments, the transmitter device can proactivelymodulate the radiation profiles based upon the energy expected to resultfrom newly formed radiation profiles based upon the predetermined SARthreshold values. For example, after determining how to generate oradjust the radiation profiles, but prior to actually transmitting thepower, the transmitter device can determine whether the radiationprofiles to be generated will result in RF energy accumulation at aparticular location that either satisfies or fails the SAR threshold.Additionally or alternatively, in some embodiments, the transmitterdevice can actively monitor the transmission field to reactively adjustpower waves transmitted to or through a particular location when thetransmitter device determines that the power waves passing through oraccumulating at the particular location fail the SAR threshold. Wherethe transmitter device is configured to proactively and reactivelyadjust the power radiation profile, with the goal of maintaining acontinuous power level throughout the transmission field, thetransmitter device may be configured to proactively adjust the powerradiation profile to be transmitted to a particular location to becertain the power waves will satisfy the SAR threshold, but may alsocontinuously poll the SAR values at locations throughout thetransmission field (e.g., using one or more sensors configured tomeasure such SAR values) to determine whether the SAR values for powerwaves accumulating at or passing through particular locationsunexpectedly fail the SAR threshold.

In some embodiments, control systems of transmitter devices adhere toelectromagnetic field (EMF) exposure protection standards for humansubjects. Maximum exposure limits are defined by US and Europeanstandards in terms of power density limits and electric field limits (aswell as magnetic field limits). These include, for example, limitsestablished by the Federal Communications Commission (FCC) for MPE, andlimits established by European regulators for radiation exposure. Limitsestablished by the FCC for MPE are codified at 47 CFR § 1.1310. Forelectromagnetic field (EMF) frequencies in the microwave range, powerdensity can be used to express an intensity of exposure. Power densityis defined as power per unit area. For example, power density can becommonly expressed in terms of watts per square meter (W/m²), milliwattsper square centimeter (mW/cm²), or microwatts per square centimeter(μW/cm²).

In some embodiments, and as a non-limiting example, the wireless-powertransmission systems disclosed herein comply with FCC Part § 18.107requirement which specifies “Industrial, scientific, and medical (ISM)equipment. Equipment or appliances designed to generate and use locallyRF energy_for industrial, scientific, medical, domestic or similarpurposes, excluding applications in the field of telecommunication.” Insome embodiments, the wireless-power transmission systems disclosedherein comply with ITU (International Telecommunication Union) RadioRegulations which specifies “industrial, scientific and medical (ISM)applications (of radio frequency energy): Operation of equipment orappliances designed to generate and use locally radio frequency energyfor industrial, scientific, medical, domestic or similar purposes,excluding applications in the field of telecommunications.” In someembodiments, the wireless-power transmission systems disclosed hereincomply with other requirements such as requirements codified under EN62311: 2008, IEC/EN 662209-2: 2010, and IEC/EN 62479: 2010.

In some embodiments, the present systems and methods for wireless-powertransmission incorporate various safety techniques to ensure that humanoccupants in or near a transmission field are not exposed to EMF energynear or above regulatory limits or other nominal limits. One safetymethod is to include a margin of error (e.g., about 10% to 20%) beyondthe nominal limits, so that human subjects are not exposed to powerlevels at or near the EMF exposure limits. A second safety method canprovide staged protection measures, such as reduction or termination ofwireless-power transmission if humans (and in some embodiments, otherliving beings or sensitive objects) move toward a radiation area withpower density levels exceeding EMF exposure limits. In some embodiments,these safety methods (and others) are programmed into a memory of thetransmitter device (e.g., memory 206) to allow the transmitter toexecute such programs and implement these safety methods.

The preceding description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the embodimentsdescribed herein and variations thereof. Various modifications to theseembodiments will be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to otherembodiments without departing from the spirit or scope of the subjectmatter disclosed herein. Thus, the present disclosure is not intended tobe limited to the embodiments shown herein but is to be accorded thewidest scope consistent with the following claims and the principles andnovel features disclosed herein.

Features of the present invention can be implemented in, using, or withthe assistance of a computer program product, such as a storage medium(media) or computer readable storage medium (media) having instructionsstored thereon/in which can be used to program a processing system toperform any of the features presented herein. The storage medium (e.g.,memory 206, 256) can include, but is not limited to, high-speed randomaccess memory, such as DRAM, SRAM, DDR RAM or other random access solidstate memory devices, and may include non-volatile memory, such as oneor more magnetic disk storage devices, optical disk storage devices,flash memory devices, or other non-volatile solid state storage devices.Memory optionally includes one or more storage devices remotely locatedfrom the CPU(s) (e.g., processor(s)). Memory, or alternatively thenon-volatile memory device(s) within the memory, comprises anon-transitory computer readable storage medium.

Stored on any one of the machine readable medium (media), features ofthe present invention can be incorporated in software and/or firmwarefor controlling the hardware of a processing system (such as thecomponents associated with the transmitters 100 and/or receivers 104),and for enabling a processing system to interact with other mechanismsutilizing the results of the present invention. Such software orfirmware may include, but is not limited to, application code, devicedrivers, operating systems, and execution environments/containers.

It will be understood that, although the terms “first,” “second,” etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the claims. Asused in the description of the embodiments and the appended claims, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willalso be understood that the term “and/or” as used herein refers to andencompasses any and all possible combinations of one or more of theassociated listed items. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

As used herein, the term “if” may be construed to mean “when” or “upon”or “in response to determining” or “in accordance with a determination”or “in response to detecting,” that a stated condition precedent istrue, depending on the context. Similarly, the phrase “if it isdetermined [that a stated condition precedent is true]” or “if [a statedcondition precedent is true]” or “when [a stated condition precedent istrue]” may be construed to mean “upon determining” or “in response todetermining” or “in accordance with a determination” or “upon detecting”or “in response to detecting” that the stated condition precedent istrue, depending on the context.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the claims to the precise forms disclosed. Many modifications andvariations are possible in view of the above teachings. The embodimentswere chosen and described in order to best explain principles ofoperation and practical applications, to thereby enable others skilledin the art.

1. (canceled)
 2. A wireless-power transmission system configured tocontrol operation of one or more power amplifiers to optimize theperformance of one or more antennas, the wireless-power transmissionsystem comprising: a power amplifier; one or more antennas; one or moreintegrated circuits configured to: adjust power provided to the one ormore antennas from the power amplifier; adjust a power distribution fora transmission field based, in part, on the adjusted power provided tothe one or more antennas from the power amplifier such that the adjustedpower provided is evenly distributed across the power distribution forthe transmission field of the one or more antennas, wherein the evendistribution of the adjusted power results in a reduced power loss at anedge of the power distribution for the transmission field of the one ormore antennas from 30% to 10%.
 3. The wireless-power transmission systemof claim 2, wherein: the one or more integrated circuits include memorystoring predetermined properties of the wireless-power transmissionsystem; and the power distribution for the transmission field of the oneor more antennas is adjusted based on the predetermined properties ofthe wireless-power transmission system and the adjusted power providedto the one or more antennas from the power amplifier.
 4. Thewireless-power transmission system of claim 3, wherein the predeterminedproperties include characteristics of the wireless-power transmissionsystem obtained during simulation, characterization, and/or manufacturetests of the wireless-power transmission system.
 5. The wireless-powertransmission system of claim 2, wherein the power provided to the one ormore antennas from the power amplifier is adjusted based on the one ormore integrated circuits detecting a change in impedance at the poweramplifier.
 6. The wireless-power transmission system of claim 5, whereinthe change in impedance at the power amplifier is detected based on oneor more of movement of a wireless-power receiver within the transmissionfield, movement of a foreign object within the transmission field, awireless-power receiver entering the transmission field, awireless-power receiver leaving the transmission field, a foreign objectentering the transmission field, and a foreign object leaving thetransmission field.
 7. The wireless-power transmission system of claim5, wherein: the one or more integrated circuits include memory storingpredetermined properties of the wireless-power transmission system; andthe change in impedance at the power amplifier is detected based on acomparison between a measured value for the change in impedance at thepower amplifier and one or more of the stored predetermined propertiesof the wireless-power transmission system.
 8. The wireless-powertransmission system of claim 2, wherein the adjusted power is selectedfrom among a plurality of available power levels.
 9. The wireless-powertransmission system of claim 8, wherein each respective available powerlevel of the plurality of available power levels is between 2 watts and15 watts.
 10. The wireless-power transmission system of claim 2, whereinthe wireless-power-transmission system includes only a single poweramplifier and the one or more antennas include only a single antenna.11. The wireless-power transmission system of claim 2, wherein the powerdistribution for the transmission field is adjusted without tuning ofthe one or more antennas.
 12. The wireless-power transmission system ofclaim 2, wherein the power distribution for the transmission field isadjusted without using beam-forming techniques.
 13. A method ofcontrolling operation of one or more power amplifiers to optimize theperformance of one or more antennas, the method comprising: atwireless-power transmission system including a power amplifier, one ormore antennas, and one or more integrated circuits: adjusting powerprovided to the one or more antennas from a power amplifier; adjusting apower distribution for a transmission field based, in part, on theadjusted power provided to the one or more antennas from the poweramplifier such that the adjusted power provided is evenly distributedacross the power distribution for the transmission field of the one ormore antennas, wherein the even distribution of the adjusted powerresults in a reduced power loss at an edge of the power distribution forthe transmission field of the one or more antennas from 30% to 10%. 14.The method of claim 13, wherein: the one or more integrated circuitsinclude memory storing predetermined properties of the wireless-powertransmission system; and the power distribution for the transmissionfield of the one or more antennas is adjusted based on the predeterminedproperties of the wireless-power transmission system and the adjustedpower provided to the one or more antennas from the power amplifier. 15.The method of claim 14, wherein the predetermined properties includecharacteristics of the wireless-power transmission system obtainedduring simulation, characterization, and/or manufacture tests of thewireless-power transmission system.
 16. The method of claim 13, whereinthe power provided to the one or more antennas from the power amplifieris adjusted based on the one or more integrated circuits detecting achange in impedance at the power amplifier.
 17. The method of claim 16,wherein the change in impedance at the power amplifier is detected basedon one or more of movement of a wireless-power receiver within thetransmission field, movement of a foreign object within the transmissionfield, a wireless-power receiver entering the transmission field, awireless-power receiver leaving the transmission field, a foreign objectentering the transmission field, and a foreign object leaving thetransmission field.
 18. A non-transitory, computer-readable storagemedium storing instructions that, when executed by a processorassociated with one or more integrated circuits of a wireless-powertransmission system, cause the one or more integrated circuits toperform operations including: adjust power provided to one or moreantennas from a power amplifier; and adjust a power distribution for atransmission field based, in part, on the adjusted power provided to theone or more antennas from the power amplifier such that the adjustedpower provided is evenly distributed across the power distribution forthe transmission field of the one or more antennas, wherein the evendistribution of the adjusted power results in a reduced power loss at anedge of the power distribution for the transmission field of the one ormore antennas from 30% to 10%.
 19. The non-transitory, computer-readablestorage medium of claim 18, wherein: the one or more integrated circuitsinclude memory storing predetermined properties of the wireless-powertransmission system; and the power distribution for the transmissionfield of the one or more antennas is adjusted based on the predeterminedproperties of the wireless-power transmission system and the adjustedpower provided to the one or more antennas from the power amplifier. 20.The non-transitory, computer-readable storage medium of claim 19,wherein the predetermined properties include characteristics of thewireless-power transmission system obtained during simulation,characterization, and/or manufacture tests of the wireless-powertransmission system.
 21. The non-transitory, computer-readable storagemedium of claim 18, wherein the power provided to the one or moreantennas from the power amplifier is adjusted based on the one or moreintegrated circuits detecting a change in impedance at the poweramplifier.